Scope Software Manual

e-corder

®

www.

eDAQ

.com

Scope Software Manual

Scope

version 4.0

for Windows and Macintosh computers

ii

Scope Software

This document was, as far as possible, accurate at

the time of printing. However, hanges may have

been made to the software and hardware it

describes since then: eDAQ Pty Ltd reserves the right

to alter specifications as required. Late-breaking

information may be supplied separately. Latest

information and information about software updates

can also be obtained from our web site.

Trademarks

e-

corder

and PowerChrom are registered trademarks

of eDAQ Pty Ltd. Specific model names of data

recording units, such as

e-

corder

201, are

trademarks of eDAQ Pty Ltd. EChem

is a trademarks

of eDAQ Pty Ltd. Chart and Scope are trademarks of

ADInstruments Pty Ltd and used by eDAQ under

license.

Mac OS, and Macintosh, are registered trademarks

of Apple Computer, Inc. Windows 98, Windows

Me, Windows 2000, and Windows XP are

trademarks of Microsoft Corporation.

PostScript is a registered trademark of Adobe

Systems, Incorporated.

All other trademarks are the respective properties of

their owners.

Document Number: U-ES200S-1103

For Scope version 4.0

Copyright © November 2003

eDAQ Pty Ltd

6 Doig Avenue

Denistone East, NSW 2112

Australia

http://www.eDAQ.com

email: [email protected]

All rights reserved. No part of this document may be

reproduced by any means without the prior written

permission of eDAQ Pty Ltd.

Scope

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Contents

1

Getting Started

1

Learning to Use Scope 2

Computer Requirements 2

Windows 2

Macintosh 2

Windows Installation

3Macintosh Installation 5Exiting Scope 5

2

Introduction

7

An Overview of Scope 8

Opening a Scope File 10

Closing a Scope File 12

The Scope Window 13

Recording 17

Display While Recording 18

Interruptions While Recording 19

Converting Quantities 30

Choosing Unit Names 32

Sweep and Trigger Controls 33

Sweep 33

Trigger 36

The Stimulator 37

Mode 37

Setting the Controls 39

Customized Stimulus Waveforms 40

The Stim Panel 41

Constant Output Voltage 42

The Stimulator Output 42

Stimulator External Trigger 43

4

Data Display

45

Data Display Area 46

Changing Channel Height 46

Overlaying Channels 46

Displaying a Single Channel 47

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its of Recording 19

etting Up Scope 21

g the Sampling Rate 22mpling Rate Limits 24nel Controls 24put Amplifier 26

gnal Display 26tering 27gnal Input Controls 27splay Offset 28Conversion 29

The Amplitude Axis 48Axis Labels 49Display Settings 50

Overlay Display Settings 52Stimulus Display Settings 53

Navigating 54Overlaying Pages 55

Using the Page Buttons 55The Zoom Window 56

5 Working With Files 61

Selecting Data 62The Selection Miniwindow 63

Editing Data 64Transferring Data 65

The Clipboard 67Saving Options 67Appending Files 70Text Files 71Printing 73

Page Setup 73The Print Command 75

Page Comments 78The Notebook 78

6 Data Analysis 81

Signal Measurements 82Using the Marker 82Setting and Removing Baselines 83The Marker Miniwindow 84

Background Subtraction 86The Data Pad 87

Adding Data to the Data Pad 88Setting Up the Columns 89

The Average Page 91The X–Y Display 92The FFT Display 93

iv

Computed Functions 95Sampling Rate 96Units 96Display Functions 96Channel Functions 97

7 Customizing & Automating 101

Preferences 102Options 102Menus 105Controls 106Start-Up 107

Special Access 108Hardware Start-Up 109External Trigger 109

Macros 110Recording a Macro 111Replaying a Macro 112Deleting a Macro 112Options When Recording Macros 113Macros Using Macros 116Macro Commands 116

Analysis Scope 123

A Menus & Commands 125

Menus 125 128Keyboard Shortcuts 129

B Troubleshooting 131

Technical Support 131Solutions to Common Problems 133

C Technical Notes 137

Fast Fourier Transforms 137Computed Functions 140

Index 143

Scope Software

License & Warranty 151

Scope
Software
1
C H A P T E R O N E
Getting Started

Welcome to Scope, software that lets you use your e-corder as a two-

channel storage oscilloscope or XYT plotter. It is one of a range of

eDAQ programs that provide a laboratory data recording and analysis

system for use with Windows or Macintosh computers.

This chapter contains instructions on the installation of Scope and

computer requirements.

1

2

Note:Actual appearance of the Scope software on your computer will vary slightly from the diagrams in this manual, depending on your operating system (Windows 98, 2000, XP, Macintosh), and your personalized display settings.

Learning to Use ScopeFirst familiarize your self with the computer’s operating system. Many of the Scope menus, dialog boxes, and controls work in a similar way to other software on your computer.

Read the introductory chapters in your e-corder Manual to be sure that the e-corder is properly connected to the computer, then continue with this chapter.

Updated documentation, and application notes, are available from our web site, www.eDAQ.com.

Computer RequirementsWindows

• A Pentium processor or better

• Microsoft Windows 98, Me, 2000, XP, or later. Windows 95 and NT will not work with e-corder units to collect data, however you can use the Scope software on these older computers to open pre-existing data files for review and analysis.

• 48 MB RAM (Windows NT 4, 2000, XP)

• 20 MB free hard disk space

• A CD-ROM drive

Scope Software

• 800 x 600, 256 color display or better

• A USB interface

Macintosh

• A Power PC, G3 or later processor

• Mac OS 8.6 or later (Mac OS 9.0 or later recommended). Classic with Mac OS X.

• 32 MB available RAM

• 20 MB free hard disk space

Chapter 1 — Getting Starte

• A CD-ROM drive

• A USB interface

Windows InstallationIt is recommended that you use the e-corder Software Installer to install both Chart and Scope software at the same time.

Insert the e-corder Software Installer CD into the computer’s CD drive. The e-corder Installer window should appear. If not, locate and double-click the Startup icon on the CD (Startup.exe if you have file extensions showing) to open it. Follow the installation instructions.

The hardware and software manuals (including this manual, the Chart Software Manual and e-corder Manual) in Adobe Acrobat portable document format (pdf) files, can are also be installed on your computer. Check our web site, www.eDAQ.com, periodically for information regarding software updates and new documentation.

You can easily access the Scope software, or its demonstration files, by using the Programs menu of the taskbar’s Start button under ‘eDAQ Scope’. A desktop shortcut to the Scope software is created during installation.

If You Have an Earlier Version of Scope…

If you have an earlier version of Scope, it will be overwritten if the new version is being installed in the same location. If your old version of

d 3

Scope is in a different location, uninstall it using the Windows Add/Remove Programs control panel. Keeping two versions of the same software on your computer is not recommended.

New Hardware

The first time you use a new e-corder unit with a computer, Windows will display the New Hardware wizard, Figure 1–1, and ask you if you want to install a driver.

Insert the Installer CD. Leave the wizard on its default settings, as shown, and click the button.

4

Figure 1–1 The New Hardware wizard

Figure 1–2 The dialog box that appears if the e-corder is not connected or switched on

Starting Your Copy of Scope

Ensure that the e-corder is connected properly to your computer (see the e-corder manual) and turned on. Double-click the Scope icon or its desktop shortcut or choose Scope from the Programs menu of the taskbar’s Start button (under eDAQ).

If the e-corder is not connected, or is not turned on, then the dialog box in Figure 1–2 will appear.

Scope Software

Chapter 1 — Getting Starte

Macintosh InstallationIt is recommended that you install both Chart and Scope software at the same time.

Insert the Software Installer CD into the computer. The e-corder Disk window should appear (if it doesn’t, double click the CD icon on your desktop).

Double-click the e-corder Installer icon to open the e-corder Installer (if you wish to install Scope only, double-click the Scope Installer icon in the Installers folder).

Exiting Scope If you want to exit Scope after opening a file, choose Exit (or Quit on Macintosh) from the File menu. If you want to proceed with working through this guide, you can leave the file open, and proceed.

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6
Scope Software

Scope
Software
2
C H A P T E R T W O
Introduction

Scope software, together with your e-corder, form a powerful data

acquisition system, with an intuitive interface, used to replace

oscilloscopes and XYT plotters.

This chapter provides a general overview of Scope, and deals with the

basics of recording signals.

7

8

An Overview of ScopeScope, together with e-corder hardware and a Windows or Macintosh computer, provides the capability of a two-channel storage oscilloscope, or XYT plotter, with added display, analysis and storage options. You can record on one or two channels at a variety of rates.

Controls and Display

See Chapter 3 for how to set up an e-corder input channel and assign it to Input A or Input B:

• input sensitivity range and filtering options can be set independently for each channel, page 24.

• sampling rate can be set up to 200 kHz, page 22.

• in addition the Stimulator, page 37, allows you to set up a voltage waveform to be output during a sweep: single, double, or multiple square pulses, ramps, or triangular or free-form waveforms can be defined. The Stim control panel, page 41, allows stimuli to be adjusted as required during recording.

Chapter 4 shows how the Scope window can be resized, and the height of each channel can be changed:

• Channel Amplitude axes, page 48, can be dragged, stretched, or set through the Scale pop-up menu.

• appropriate axis labels, page 49 (and units of measurement, page 29) for each channel can be assigned.

Scope Software

The data display can be set to show one or both channels, page 96.

Recording

Scope records data in sweeps, Chapter 3, like a normal storage oscilloscope:

• you can choose to record one or two channels of data in single, repetitive, multiple, superimposed, or average sweeps, page 33.

• each sweep can be recorded to a different Scope ‘page’.

Chapter 2 — Introduction

• Triggering options, page 34, allow you to control when Scope starts and stops recording.

In addition:

• Page Comments, page 78, can be made for each page of data to mark features of interest, or

• the Notebook can be used, page 78, to make general notes for inclusion in the data file.

Saving, Printing, and Editing

Scope recordings can be printed, edited, and saved to a disk for later review, Chapter 5:

• save the settings of any Scope file to enable an experiment to be quickly reconfigured, page 68.

• sweeps can be printed in a variety of formats, or cut, copied, and pasted between files, page 64.

• append a Scope file to the end of an open file, page 70.

• export data to other software, such as statistics programs or spreadsheets, or paste or import correctly formatted text into a Scope file, page 65 & 71.

Analysis

After recording, you can make measurements directly from the recording, and display the signals in various ways to facilitate the analysis, Chapter 6:

9

• use the Marker, page 82, as an origin/reference point.

• the Data Pad internal speadsheet, page 87, can extract parameters about selected regions of the signal (such as mean and standard deviation values, slopes, integrals etc.). It is saved with the data file.

• plot data from one channel versus another (XY plotting), page 92

• perform a Fast Fourier transform (FFT, page 93) of the signal to display a power spectrum.

• A range of computed functions, page 95, can be applied to the incoming signal, such as smoothing, integration, differentiation, etc.

10

Figure 2–1 Scope icons

NoteHold down the Ctrl key ( key on Macintosh) as you start Scope to open with the default settings.

The signals on the two channels can be added to, subtracted from, or multiplied by one another. These functions can also be undone revealing the original, raw data.

• set a background page, page 86, the signals of which are subtracted from other pages in the file.

You can also:

• use the Zoom window, page 56, to examine a section of signal in detail.

• or overlay signals from any selection of pages, page 55.

Customizing

Scope can be extensively customized, Chapter 7:

• Controls, and menus and their commands (and keyboard shortcuts) can be locked, hidden, or altered, page 105, to simplify the appearance of Scope for student or routine use.

• Macros, page 110, can be created to automate commonly used sequences of commands.

Opening a Scope FileHave a Scope file open while working through this manual, so that you can try the commands, controls, and settings as they are discussed. First, make sure that the e-corder is properly connected to your computer, and is turned on. If an e-corder is not connected, then on

Scope Software

opening a file, a dialog box, Figure 1–2, page 4, offers the Analysis option to use Scope for viewing and analyzing extisting data files.

To start Scope, double-click:

• , the Scope program icon, Figure 2–1, which will open a new untitled file;

• , a Scope file icon, which will open a data file; or

• , a settings file icon, which will open a preconfigured settings file (containing no data), page 68, ready to begin recording. Macro files, page 110, also use this icon.


Figure 2–2 The Open directory dialog box on a Windows computer. The corresponding dialog box on Macintosh has similar options.

On a Windows computer you can also use the desktop shortcut, to open Scope, or the taskbar Start button — the default location is Start>All Programs>eDAQ>Scope.

If Scope is already open then you can open another file or create a new one by choosing Open… or New from the File menu, Figure A–2, page 126. Choosing Open… from the File menu accesses the Open directory dialog box, Figure 2–2. Only one file can be open in Scope at any one time.

On Windows computers data file names end with ‘.sfwdat’; settings files with ‘.sfwset’; and macro files with ‘.sfwmac’. This filename suffix should always be present on a Windows computer, although it may be

Select a file format

Select a file to open

11

hidden. If a file has been moved from a Macintosh to a Windows computer then it may not have the suffix, and you can use the All files file format option to locate it. Text files, page 71, can also be imported, using the All files or Text files options.

The information in a Scope file is made up of data and settings. Data are the recorded signals, which are normally loaded when opening a file. Settings are of two sorts:

• recording settings, such as the sampling rate, channel input sensitivity range, triggering options, and stimulator waveform output;

12

• display settings, such as window size, display settings, and menu configuration.

If the checkbox is ticked when opening a Scope file, Figure 2–2, then both recording and display settings are loaded. Opening a file with the checkbox off will load only display settings, not those affecting recording. In either case, settings will apply to any subsequent sweep.

If a data file is already open, it will be closed when another data file is opened. If the checkbox is ticked, then both the settings and the data will be loaded, otherwise the settings of the original data file are retained.

The use of the checkbox to append files is discussed on page 70.

The use of the checkbox to discard macros is discussed on page 114.

There is a demonstration data file (in the Scope>Demo Files folder).

Closing a Scope File

To close a Scope file, choose Close from the File menu, Figure A–2, page 126, or type Ctrl+F4. To exit Scope, choose Exit (or Quit on Macintosh) from the File menu, or type Alt+F4 ( –Q on Macintosh).

Scope Software


File title

Scale pop-up menu, page 48

Amplitude axis, page 48

Page comments

The Display modpop-up menu

Marker

Channel titles

Scaling buttons

Figure 2–3 The Scope window

The Scope WindowThe essential controls for recording data are provided in the main Scope window and its various control panels, Figure 2–3, and the Scope menu bar, Figure 2–4. The Scope Window command from the
Windows menu returns to this window from another, or opens a new, untitled file if the window has been closed.
13

Basic Window Controls

The title bar shows the title of the file, and is highlighted it if it is active (that is, the frontmost window). Drag the title bar to move the Scope window. Drag the size control or window borders to set the size of the window: this does not affect recording fidelity — the resolution of recorded data is independent of the resolution of the display. Click the close button to close a currently open Scope file (equivalent to choosing Close from the File menu, Figure A–2, page 126).

Title bar, drag to move

Signal display area

Drag channel separator to adjust channel areas

e Re-size control

Set sampling rate, and sweep duration

Start/stop recording

Set input channel sensitivity and filtering

Page buttons — select the sweep to display

Cursor coordinates Shift+drag a panel title to move the panel

14

Average page

Blank (last) page

Active (highlighted) page)

Page Corner controls

Scrolling buttons

Figure 2–4 The Scope menu bar

Six control panels (e-corder, Cursor, Input A, Input B, Time Base, and Sample) can be moved around the screen independently by Shift+dragging their titles. Blank panels appear behind the control panels to hide the background.

The Scope menu bar, Figure 2–4, contains the Scope menus, see Appendix A, page 125.

On Windows computers, the Scope menu bar can be moved around by dragging its title bar, and resized horizontally by dragging its borders. Click its close button to quit Scope, or its minimize button to reduce Scope to a button on the taskbar (you can do this while sampling).

Navigating

Scope stores sweeps of data as if they were pages in a notepad. The numbered Page buttons along the bottom of the Scope window and the Page Corner controls at the bottom right of the data display area allow you to move to, and view, the multiple pages of a Scope file. The highlighted (dark) Page button, , indicates the page of data currently viewed, the active page. The Average page always precedes run 1, and a blank page, , always appears as the last button. Pages of data are numbered consecutively as they are recorded. Click the upper folded corner of the Page Corner controls to move a page right, and the lower corner to move left. Click a numbered Page button to go to

Windows computers

Macintosh

Scope Software

that page, or choose Go To Page… from the Display menu, and enter the number in the dialog box that appears. You can also go to the page to the left or right by using the left or right arrow keys on the keyboard, respectively. Hold down the Ctrl key ( key on Macintosh) while pressing the left or right arrow key to go to the beginning or the end of the file (the first or last numbered pages with data, not the Average or blank pages).

When there are too many sweeps to accommodate all the buttons along the bottom of the window, then left and right scrolling buttons appear, and , click them to move left or right, or press them to scroll left or right continuously.


Channel pop-up menu

Rate/Time display

The Scope Axes

The horizontal axis of the data display area, Figure 2–3, page 13, shows:

• the time from the start of sampling for Scope display, page 13;

• x-values, for XY displays, page 92; or

• frequency, for FFT (Fast Fourier Transform) displays, page 93;

depending on the option chosen from the Display pop-up menu (at the bottom left of the window).

The vertical Amplitude axis indicates the size of a signal. Note that the axis area remains blank until a signal is actually recorded. The scale for each channel is initially set by the range control on the right side of the window, but can be stretched or offset using the pointer to drag the axis ticks and tick labels up and down, page 49. Display options can be chosen from the Scale pop-up menu, page 48. Units are volts by default, but the signal can be recalibrated to show any units using Units Conversion, page 29.

The Channel Controls

The channel controls are located at the right of the main Scope window, Figure 2–3, page 13. The three control panels are Input A, Input B (page 24), and Time Base, (page 22). These controls are disabled if Scope is operating in Analysis mode, Figure 1–2, page 4.

Press the The Input A or Input B Channel pop-up menu to turn off or on the display channel, or to choose from which of the e-corder input

15

channels to record. The number of channels available depends on the model of e-corder. Press the Range pop-up menu to select channel range/sensitivity. Click the button to display a dialog box, Figure 3–3, page 25, to preview the signal and set sensitivity and filtering controls. The Range pop-up menu and button are disabled if the input is turned off.

The Time Base panel, Figure 3–1, page 22, provides control of sampling rate and recording resolution for both Scope channels. Press the Samples pop-up menu to choose the number of samples per sweep, and choose the approximate duration of each sweep from the Time/Freq pop-up menu. The Rate/Time display to the right of the

16

panel title display shows the sampling rate currently set. The preferences can be changed from the default for this panel so that the time base is set by division or by frequency: double-click the Rate/Time display to access the dialog box to change them, Figure 7–1, page 103.

Data Display Area

Recorded data are shown in the main Scope window, Figure 2–3, page 13, in the data display area. Two channels are displayed by default. The channel separator between them can be dragged up or down to vary the size of the channel display areas. Dragging it to the top of the display or double-clicking it overlays the two channels. See Chapter 4, page 45 for more information about how to display signals.

Waveform Cursor Display

The Waveform Cursor display, in the Cursor panel, shows the time and the signal value of the Waveform Cursor in both channels, when the pointer is over the data display area, Figure 6–1, page 82.

The Marker

The Marker, , page 82, can be found at the bottom left of the Scope window, Figure 2–3, page 13. It can be dragged from its home position onto the data display area to set a particular data point on a waveform as a zero reference point, so that relative measurements can be made. Double-clicking the Marker or clicking its home box recalls it.

Scope Software

Page Comment Button

The Page Comment button, , can be found at the bottom left of the Scope window, Figure 2–3, page 13. Click it to display the Page Comment window, Figure 5–17, page 78, for noting down comments about particular pages of data. If comments have been made, then the button icon toggles to .

Start Button

To start recording, click the button. The button toggles to , click it, if required, to stop recording. During starting or


stopping, or if the e-corder or computer is busy the button will appear as . Don’t click the button repeatedly: wait until sampling has definitely started or stopped.

Pointer

The pointer position is controlled by moving the mouse, and will change shape, for example, , giving an indication of its function, as you move it over various objects in different parts of the monitor.

RecordingTo start recording, click the button in the Sample panel. The button then toggles to : click it, if required, to stop recording. The button may display Wait… while starting or stopping, if the e-corder or computer is performing other tasks. Note that Scope can record in the background: it does not need to be the active application to record data.

Scope can record a large number of sweeps as sequential ‘pages’ of data. You can choose to record one or two channels of data per page in a variety of sweep modes, page 33:

• Single displays and records a single page of data;

• Repetitive displays repeat scans, but only records the last page of data;

17

• Multiple records multiple pages of data;

• Superimposed records sweeps one atop the other on the same page, dimming the older sweeps — only the last sweep is finally recorded; and

• Average records the average signal from a number of successive sweeps on a single page.

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at a slow sampling rate

Figure 2–6 Progress Indicator display

Display While Recording

At slow sampling rates (less than 400 Hz), the signal is drawn on the screen from left to right, much like a standard oscilloscope. A short vertical line segment, the Trace Indicator, Figure 2–5, moves left to right across the top of the data display area, tracking the front edge of the advancing waveform. If repetitive recording is chosen, then when the right edge is reached, drawing starts again at the left (and old data are erased to make way for the new data).

At fast sampling rates, the signal is collected too quickly to be displayed in real time and the sweep is drawn after it has been processed. Some information is given on the sampling status of Scope in the e-corder panel, below its title (see Figure 2–6). The message ‘Sampling…’ will be displayed during single-sweep sampling, or when Scope is waiting for a trigger. If sweeps are repetitive or superimposed, a progress indicator, , will appear to the left of this message. If multiple or average sweeps are chosen, then after sampling has started, the Progress Indicator, , will be displayed, and the message will show the number of the sweep (‘Sweep 1’, ‘Sweep 2’ etc.). Other messages will appear in some circumstances, for instance, when loading and saving files, and recording and playing macros.

Trace Indicator
Figure 2–5 Display during recording
Scope Software


To stop recording also use Ctrl+. (or –. on a Macintosh)

Interruptions While Recording

If you make changes to various parameters, such as the sampling rate and channel range settings, while recording then Scope stops sampling on the current page, changes to the new settings, and starts sampling again. This is useful for observing signal changes doing repetitive or superimposed sweeps. It is usually recommend to stop sampling before changing settings, by clicking the button in the Sampling panel, or typing Ctrl+. , i.e. Ctrl+period character ( –. on a Macintosh).

If you are taking multiple or average sweeps, page 38, then changing recording paramters, first stops recording then starts again with the new settings. For example, if you were recording eight mutiple or average sweeps, recording would stop and then start so that eight new seeps would be performed.

Changes to the display, such as resizing the window, will also interrupt then restart sampling.

Limits of Recording

Scope can have a maximum 999 pages in any one file, provided you have sufficient free disk space available.

The size of a Scope data file depends on the number of data points per sweep (up to 2560), and whether you are sampling on one or both channels. Scope also compress the data for storage for increased efficiency.

19

Each data point is stored as a 32 bit floating point number and requires four bytes of storage. Recording on both channels at the maximum of 2560 samples per sweep would use 4 × 2 × 2560 = 20 480 bytes, that is 20 K of memory per page. Thus the largest possible Scope data file, 999 pages at 20 K per page would have a size of 20 MB.

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Scope Software

Scope
Software
3
C H A P T E R T H R E E
Setting Up Scope

This chapter describes basic settings controls such as the sampling rate

and the input amplification (sensitivity), together with features such as,

units conversion, sweep mode, triggering, and stimulation.

21

22

Figure 3–1 The Time Base panel. Select the version of the panel via the Time Base control options, Figure 7–1, page 103.

Setting the Sampling RateLike a standard oscilloscope, Scope graphs a signal against time in a series of sweeps. The Time Base panel, Figure 3–1, controls the duration of a sweep, sampling rate, and number of samples per sweep. Note that these parameters are not independent: any two defines the third. Both Scope channels always have the same time base controls.

Like the screen of a standard oscilloscope, the data display area is marked into divisions by a graticule, or grid, aligned with the tick marks on the Time axis (see Display Settings, page 50 if you want to change the appearance of the graticule). Scope always displays 12.8 divisions along the time axis, so the number of samples per division is determined by the number of data points (samples) per sweep. For example, 256 samples per sweep = 20 samples × 12.8 divisions.

The Time Base panel can be displayed in three different ways, Figure 3–1. It is possible to configure sampling by time per sweep, time per division, Table 3–1, or by sampling frequency, Table 3–2. Note that using the sampling frequency gives access to the widest range of settings. See also Sampling Rate, page 96.

Sampling rate,1 Hz – 200 kHz

Double click to access Time Base control options, Figure 7–1, page 103

Select the number of data points, 256 – 2560 per sweep

Interval

Scope Software

Select sweep duration setting, 1 ms – 200 s. Actual duration is 1.28 times longer

Sampling rate,1 Hz – 200 kHz

Select the duration per division (200 µs – 5 s)

between sample points (5 µs – 1 s)

Select samples per division (20 – 200)

Select the number of data points,(256 – 2560) recorded in one sweep

Chapter 3 — Setting Up Sc

Table 3–1 Sampling rates available when sweep duration, or duration per division, is used to adjust the Time Base.

Table 3–2 Sweep durations when using sampling rate (frequency) to adjust the Time Base.

Samples 256 512 640 1024 1280 2560

Time Division 20 40 50 80 100 200

200 s 20 s 1 2 – – 4 10

100 s 10 s 2 4 – – 10 20

50 s 5 s 4 – 10 – 20 40

20 s 2 s 10 20 – 40 – 100

10 s 1 s 20 40 – – 100 200

5 s 500 ms 40 – 100 – 200 400

2 s 200 ms 100 200 – 400 – 1 000

1 s 100 ms 200 400 – – 1 000 2 000

500 ms 50 ms 400 – 1 000 – 2 000 4 000

200 ms 20 ms 1 000 2 000 – 4 000 – 10 000

100 ms 10 ms 2 000 4 000 – – 10 000 20 000

50 ms 5 ms 4 000 – 10 000 – 20 000 40 000

20 ms 2 ms 10 000 20 000 – 40 000 – 100 000

10 ms 1 ms 20 000 40 000 – – 100 000 200 000

5 ms 500 µs 40 000 – 100 000 – 200 000 –

2 ms 200 µs 100 000 200 000 – – – –

1 ms 100 µs 200 000 – – – – –

Frequency (Hz)

Time per Sample

Number of Samples

256 512 640 1024 1280 2560

1 1 s 256 s 512 s 640 s 1024 s 1280 s 2560 s

2 500 ms 128 s 256 s 320 s 512 s 640 s 1280 s

4 250 ms 64 s 128 s 160 s 256 s 320 s 640 s

10 100 ms 25.6 s 51.2 s 64 s 102.4 s 128 s 256 s

20 50 ms 12.8 s 25.6 s 32 s 51.2 s 64 s 128 s

40 25 ms 6.4 s 12.8 s 16 s 25.6 s 32 s 64 s

ope 23

100 10 ms 2.56 s 5.12 s 6.4 s 10.24 s 12.8 s 25.6 s

200 5 ms 1.28 s 2.56 s 3.2 s 5.12 s 6.4 s 12.8 s

400 2.5 ms 640 ms 1.28 s 1.6 s 2.56 s 3.2 s 6.4 s

1000 1 ms 256 ms 512 ms 640 ms 1.024 s 1.28 s 2.56 s

2000 500 µs 128 ms 256 ms 320 ms 512 ms 640 ms 1.28 s

4000 250 µs 64 ms 128 ms 160 ms 256 ms 320 ms 640 ms

10 000 100 µs 25.6 ms 51.2 ms 64 ms 102.4 ms 128 ms 256 ms

20 000 50 µs 12.8 ms 25.6 ms 32 ms 51.2 ms 64 ms 128 ms

40 000 25 µs 6.4 ms 12.8 ms 16 ms 25.6 ms 32 ms 64 ms

100 000 10 µs 2.56 ms 5.12 ms 6.4 ms 10.24 ms 12.8 ms 25.6 ms

200 000 5 µs 1.28 ms 2.56 ms 3.2 ms 5.12 ms 6.4 ms 1.28 ms

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Sampling Rate Limits

The maximum sampling rate is 200 000 samples per second, corresponding to one sample every 5 µs, or 100 µs per division. This speed is available on one channel only — that is, you must turn one input channel off, or select the same channel for both inputs. At sampling rates of 100 000 /s, or less, you can record signals on both channels. Also, not all Trigger sources can be used at the 200 000 /s setting. When Scope records at fast rates, sampled data are stored in the internal memory of the e-corder and are transmitted to the computer after sampling has been completed.

Delays Between Sweeps

The computer you are using does not limit the sampling rate of the sweep, but may affect how quickly data can be displayed after collection, and also the minimum delay between consecutive sweeps. Usually these limitations are only noticeable at higher recording speeds when doing multiple repeat sweeps. Less powerful computers will have longer minimum delays between sweeps. Shorter delays can be obtained by shrinking the Scope window to its smallest size, reducing the color depth of the display, and applying any transformations (computed functions) to your data after sampling.

Channel ControlsScope has two independent Input panels, Input A (Figure 3–2) and Input B. Each allocates an e-corder channel to Input A or B, and is used

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to adjust the signal range and filtering options.

Press the Channel pop-up menu to turn off a channel, or to select the e-corder input channel from which to record a signal.

The Range pop-up menu lets you select the e-corder input channel range (sensitivity). The default setting is 10 V (from –10 V to +10 V). If the signal is too small at that range, select a more appropriate value. For the best resolution, the input range should be selected to just accommodate the maximum amplitude of the signal. If the signal exceeds the selected range then it will be truncated and that portion of the signal is lost.


Figure 3–2 An Input panel and its pop-up menus: Channel and Range

Figure 3–3 The Input Amplifier dialog box

Range pop-up menu. Set the range (sensitivity) of the input channel

Click here to access the Input Amplifier dialog box, Figure 3–3.

Turn off the input, or select the e-corder input channel from which to record

Range pop-up menu

Pause/Scroll button

High pass filter

Amplitude axesSignal average

Scale pop-up menu, page 48

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Signal input controls page 27

Click to access Input Voltage dialog box, Figure 3–4, page 28

Click to access Units Conversion dialog box, Figure 3–5, page 29

Signal is previewed in this display area

Invert signal polarity, page 28

Low pass filters, page 27

Signal average

26

The Input AmplifierClicking the button of the Input A or Input B control panels, Figure 3–2, accesses the Input Amplifier dialog box for that input channel, Figure 3–3, which allows you to adjust channel sensitivity and signal filtering. The incoming signal is previewed in display area but is not recorded to disk.

Clicking the OK button to apply the changes updates the corresponding settings seen in the main Scope window.

Signal Display

The incoming signal is displayed so you can preview the effect of changing the settings. Slowly changing waveforms will be represented quite accurately, whereas quickly changing signals will be displayed as a solid dark area showing only the envelope (shape) of the signal formed by the minimum and maximum recorded values. The average signal value is shown at the top left of the display area.

Stop the signal scrolling by clicking the Pause button, , at the top right of the data display area. It then changes to the Scroll button, , which is clicked to start scrolling again.

Shift and stretch the left hand vertical Amplitude axis to make the best use of the available display area, by dragging the axis ticks and tick labels. Controls, such as the Scale pop-up menu, function identically to those in the main Scope window. Changes made in the Input Amplifier dialog box, update the corresponding settings in the main Scope

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window, page 48.

Setting the Range

The Range pop-up menu, lets you select the input range or sensitivity of the channel. Changing the range in the Input Amplifier dialog box will update the main Scope window when the button is clicked.


Filtering

Scope can apply various filters to the incoming signal:

• AC Coupling. When the checkbox is selected, Figure 3–3, a high pass filter (cut-off frequency 0.16 Hz) is applied, removing DC and low-frequency components of the signal. The AC coupling option is useful to measure a rapidly oscillating signal, such as a vibration or sound, where it is desirable to remove DC offset.

• Low-Pass Filtering. The Filter pop-up menu, Figure 3–3, gives a choice of low-pass filters to remove high-frequency components, such as noise, from an input signal. When the Off position is selected the signal is recorded at the full 20 kHz bandwidth of the e-corder unit. These filters are implemented with a digital algorithm within the e-corder and range from 2 kHz to 1 Hz.

See also the e-corder Manual for details.

Signal Input Controls

The and checkboxes, Figure 3–3, are set depending on the type of signal being recorded. These checkboxes do not appear where the input for a channel is only single-ended (for example channels 3 and 4 of an e-corder 401). The two checkboxes allow you to set up three possible input modes:

• Positive. Use this setting when the signal is connected to a BNC input connector on the e-corder front panel. Such signals are termed single-ended, and have a + component (connected to the BNC

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centre pin) and a ground reference (the shell of the BNC connector).

• Negative. It is unusual to use this option by itself. The signal must be connected to the ‘signal –’ and ground pins of an e-corder Pod port. It is similar to the single-ended configuration above, except that positive signal will be shown as a negative voltage.

• Differential. When both the Positive and Negative checkboxes are checked, both + and – inputs (available on the e-corder Pod port) for that channel are used. The displayed signal is the difference between the positive and negative input signals.

Details of connectors can be found in the e-corder Manual.

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Figure 3–4 The Input Voltage dialog box

Inverting the Signal

The checkbox, Figure 3–3, page 25, when ticked, inverts the signal on the screen. For example, you might be recording from a force transducer where an increase in force downwards gives a negative signal, but you want to have a downwards force shown as a positive signal on the screen.

Display Offset

Clicking the button, Figure 3–3, page 25, causes the Input Voltage dialog box to appear, Figure 3–4. If the transducer or signal preamplifier that you are using has offset adjustment capabilities, you can use this display to help zero the signal before starting recording. This display is unavailable when the AC checkbox is ticked. AC coupling removes all DC components of the signal.

Direction in which to adjust offset

Signal value

Scope Software

Units

Clicking the button, Figure 3–3, page 25, accesses the Units Conversion dialog box, Figure 3–5, allowing you to calibrate the signal in units of your choice. The waveform currently in the data display area of the dialog box is transferred to the data display area of the Units Conversion dialog box. (Use the Pause button to capture any specific signal you want to use.) The units conversion will only apply to subsequently recorded signals, so it is more limited than choosing units conversion directly, as it does not allow the conversion of individual pages of data.


Value button

Difference button

Amplit

Axis label(if any)

Applied units

Data Use pop-up menu

Figure 3–5 The Units Conversion dialog box

Units ConversionUnits conversion is used to calibrate the signal, applying appropriate units for the display. You can apply the conversion before you start recording (all pages recorded can then be scaled to the required units), or you can apply it after you have made a recording, either to all or
just some of the pages. Each page could have a separate calibration if required. You need to set up units conversion separately for each of the two channels.
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There are two ways to access the Units Conversion dialog box, Figure 3–5:

• select the Units Conversion… command from the Scale pop-up menu, Figure 4–4, page 49, in the main Scope window. If a channel (or page) has no data, the Units Conversion… command is disabled. If there is a signal in the chosen channel, then it is shown in the Units Conversion dialog box. Units can be applied to all pages in the file, or just to the current page.

Unit pop-up menu

Raw signal values

Number of decimal places for display

Calibration values

ude axis Maximum, mean, and minimum values in selection

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• click the button in the Input Amplifier dialog box, Figure 3–3, page 25. The data displayed in the Input Amplifier dialog box is shown in the data display area of the Units Conversion dialog box. The units conversion will only be applied to subsequently recorded signals.

Converting QuantitiesTwo pairs of calibration points are used to calculate the scaling of the signal in the new units. Note that if the slope is negative, the Amplitude axis will be inverted.

Entering Values

If you know the relationship between the quantity being measured and the raw voltage signal, then you can directly enter the calibration values in the four boxes. For example if you are using a temperature transducer where a 1 V signal corresponds to 10 °C, and 3 V to 30 °C, then you enter values for the top row and

for the second row, and then choose °C from the Units pop-up menu.

You can set up units conversion using some values from data points, averages, and changes in the waveform shown in the data display area. The Data Use pop-up menu changes which buttons are available for data transfer: either Point 1 and Point 2 or Point 1 and Difference. This in turn fixes how displayed data are used: you can either use two data points (or averages) or a point and a difference to fix the conversion scaling. (At least one of the base values must be absolute.)

Scope Software

You can shift and stretch the vertical Amplitude axis to make the best use of the data display area. It is the same as the Amplitude axis in the main window, and the controls function identically. If you click in the data display area, a vertical line indicates the active point, and an indicator arrow at the right of the data display shows the point of intersection with the waveform (Figure 3–6, ➊). If you make a selection in the data display area, the indicator arrow at the right of the data display shows the average amplitude of the waveform, and two markers above and below it indicate the maximum and minimum data points in the selection (Figure 3–6, ➍).


Figure 3–6 Selections in the data display area of the Units Conversion dialog box

If there is an active point or a selection in the data display area, then clicking the Value button enters the voltage value (at the active point, or the average of the selected data) in the left box in its row. Clicking the Difference button enters the difference between the maximum and minimum of the selection in the left box in its row. Differences are indicated by a delta prefix (∆). In each case, the right box of the row is selected so that you can type in the known value in the new units. As a shortcut, you can double-click in the data display area to transfer the data at a point in one step (doing this a second time enters data in the unused row).

For example, to calibrate a force transducer:

1. start recording slowly (about 4 /s) and apply first one and then a second known force (calibration weight) to the transducer during a

➊

➋

➌

➍

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sweep.

2. click on the channel you want to calibrate and choose Units Conversion… from the Scale pop-up menu, Figure 4–4, page 49, to open the Units Conversion dialog box, Figure 3–5, page 29.

3. choose the 2 Point Calibration option from the Data Use pop-up menu, then use the pointer to select a point or area in the signal corresponding to the first calibration force (Figure 3–6, ➋)

4. click the button, Figure 3–5, page 29, to enter its value in the upper raw signal text box, and type the known force in corresponding calibration value box beside it.

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Figure 3–7 Dialog boxes for defining and deleting units

5. repeat the process for the other force (Figure 3–6, ➌), entering data in the lower raw signal and calibration value text boxes.

An example where you might use the Point and Difference method is for a temperature transducer that produces an accurately known change in voltage for a given change in temperature (such as ∆20 mV giving ∆1 °C) but has a relatively large offset error. Record the signal at an accurately known temperature (say, 23.6 °C, at ambient). Use this value in the top row to correspond to the measured signal. Use the Difference button to enter the 20 mV and 1 °C values in the second row.

You can also determine a difference by selecting a region where the signal varies (Figure 3–6, ➍)and clicking the button.

Choosing Unit Names

The Unit pop-up menu, , Figure 3–5, page 29, can be used to select, define new, or delete old, unit names. Unit names are stored in the e-corder Settings file in the System folder in the eDAQ folder, and are available in all Scope for Windows files once created (or unavailable if deleted).

Select Define Unit… from the Units pop-up menu to access the Define Unit Name dialog box, Figure 3–7, to define new unit names. Unit names can be up to nine characters long, with an additional order of magnitude prefix. Superscripts, subscripts and special characters can be entered in the same way as for axis labels, page 49. You can delete unwanted unit names by choosing Delete Unit… from the Units pop-up

Scope Software

Type the unit name in here — superscripts and subscripts are possible

Select a prefix from this pop-up menu


menu: the Delete Unit Name dialog box appears, Figure 3–7. Select the unit to be deleted from the scrolling field, Ctrl+click ( -click on Macintosh) or Shift+click to select several, and click OK to delete the unit and close the dialog box. Double-click a unit name to delete it immediately.

You can set the number of decimal places of the new units (from 0 to 6), by clicking the arrows. You can turn units conversion off or on without losing the values you have entered by clicking the

buttons. Click the button to see how the units converted axis will appear, or the OK button to convert units and return to the main Scope window.

Sweep and Trigger ControlsThe Sampling… command in the Setup menu, Figure A–5, page 126, accesses the Sampling dialog box, Figure 3–8, with the sweep and trigger controls.

A sweep is the recorded and displayed waveform that fills one Scope page. You can choose the sweep method used by Scope: sweeps may be single, repetitive, multiple, averaged, or superimposed. When multiple or averaged sweeps are chosen, you can set the number of sweeps, and for all modes except single, you can set the delay between the sweep starting times.

Triggering determines the way in which Scope starts and stops recording. A trigger is an event such as clicking the Start button or a voltage above some preset threshold in an incoming waveform. The

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active trigger controls in the Sampling dialog box depend on the sweep control settings. You can use the controls to set up the type of trigger event you want, the delay until recording, and so on.

SweepThe Mode pop-up menu, Figure 3–8, selects the way that Scope samples and then displays data:

• Single. This is the default setting. One sweep is recorded at a time. A new sweep is started only when a new source event occurs: clicking the Start button, or a new trigger signal is received

34

Source pop-up menu. Select the action that starts a sweep

Exact values are displayed below the slider bar

Mode pop-up menu. Select the type of sweep

Start pop-up menu. Choose how Scope reacts to the trigger event

Figure 3–8 The Sampling dialog box; Sweep and Trigger controls

• Repetitive. Sweeps are displayed successively on the same page, each overwriting (and erasing) the previous sweep. Sampling stops when the Stop button is clicked. Only the last sweep is recorded permanently.

• Multiple. The specified number of sweeps is made, each sweep on a new page. The Sample control, , lets you set the number of sweeps, from 2 to 999. Ensure that the total of the number of pages already sampled plus the number to be sampled does not exceed 999, and that there is enough memory for the
operation.
• Average. The specified number of sweeps is made, with the average value of the sweeps is displayed after each sweep.

Scope Software

Average mode is useful to reduce noise in a repeating signal, or to average out variations between individual sweeps. Only the average sweep is recorded permanently. When Average is chosen, the Average control, , can be set from 2 to 2048 individual sweeps to be used for averaging.

• Superimpose. Sweeps are displayed successively on the same page, but previous sweeps are not overwritten. Each new scan is overlaid on previous sweeps. Clicking the display while sampling

Choose to trigger on an upwards or downwards sloping signal

Set the interval between successive sweeps

Use the slider bar or text entry button to set values

Click the arrow buttons to set the number of sweeps of data


clears the previous sweeps. Sampling stops when the Stop button is clicked, and only the last sweep is recorded permanently.

Scope will sample in the chosen mode until you choose a new one. By default, sampling starts on the blank (last) page of the current file, even if the active (viewed) page was earlier in the file. Multiple mode creates the number of blank pages it needs before sampling, Other modes add a new blank page after sampling.

The Delay control, , sets the interval between the start of consecutive sweeps in repetitive, multiple, averaged, or superimposed modes. The delay should normally be greater than the sweep time. Type a value in up 9999 seconds in increments of 0.1 seconds.

The minimum delay is affected by the speed of the computer. If the delay is set to less than the sweep time, a new scan is started as quickly as possible, the actual delay is then dependent of the speed of the computer.

Clicking the Start button in the main Scope window, Figure 2–3, page 13, prepares Scope to record, the chosen trigger event starts Scope recording.The Source pop-up menu, Figure 3–8, selects the trigger event:

• User. Sampling will be triggered when you click the Start button in the main Scope window. Other triggering options are inactive.

• Input A, or Input B. Triggering is activated when the signal reaches a threshold value. The channel must be turned on for its signal to be used as a triggering event! The Level control is used to

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set the trigger level voltage, and is only active in this mode.

• External. Triggering is activated when a signal is received via the external Trigger connector on the e-corder front panel. See your e-corder Manual for exact specifications.

• Line. The trigger event comes from a cycle of the mains power (50 or 60 Hz frequency) which is automatically monitored by the e-corder. This can useful if you are recording a signal derived from AC current, such as mains transformer output, or for monitoring fast scans affected by mains hum, where it is desirable to always start in the same position of the hum cycle so that successive sweeps appear to have the same baseline.

36

User and External options can be used in conjunction with the Stimulator, page 37. Input A, Input B, and Line options cannot be used if the Stimulator is also being used.

Trigger

A trigger is an event such as clicking the Start button (User triggering), or when a threshold been reached by the incoming signal, and can be used to start or stop Scope recording. The available trigger options depend on the mode and source that are chosen in the Sweep section of the Sampling dialog box Figure 3–8, page 34. Three trigger modes are available from the Start pop-up menu:

• At Event. This is the default mode. Sampling starts as soon as the trigger threshold is reached;

• Post-Trig. With post-triggering, sampling starts a set time after the trigger event occurs, at a time preset with the Delay control (up to a maximum delay of about eight sweep durations).

• Pre-Trig. With pre-triggering, sampling starts before the trigger event occurs. The pr-trigger time is set with the Delay control, up to a maximum of one sweep duration. The Time axis will have negative values for the period preceding the trigger event (zero time). Starting a sweep in this mode causes Scope to immediately monitor the signal. When a trigger event occurs, the data in the pre-trigger period is saved, along with the subsequent portion of the sweep. Pre-triggering will ignore trigger events that occur before the pre-trigger duration has expired: if you set the pre-trigger to 20 ms, Scope will monitor the signal for 20 ms before accepting a trigger event.

Scope Software

There should only be one trigger event per sweep, whatever the mode of recording, if the sweeps are to be synchronized.

The slope controls, , usually determine whether triggering occurs when the signal goes up, or down, through the trigger level (threshold). In the event of contact closure triggering, using the External trigger connector, page 109, the slope controls determine whether triggering occurs on going from open to closed circuit, or closed to open circuit respectively.


Figure 3–9 The Trigger Marker, , or , in the main Scope Window

If Input A or Input B have been selected as source of the trigger event, then the trigger threshold level and slope can be adjusted from the main Scope window by dragging the Trigger Marker, , Figure 3–9, up or down to adjust the threshold level. Double-clicking the Trigger Marker toggles it between and , reversing the slope control.

The StimulatorThe Stimulator… command, available in Setup menu, Figure A–5, page 126, accesses the Stimulator dialog box, Figure 3–10, which is used to configure waveforms (pulses, ramps, etc.) to be sent via the sockets marked ‘Output’ on the front of the e-corder.

The Stimulator can only be used at recording speeds greater than 2 Hz. Alos must be used in conjunction with the User or External trigger (At Event) source settings, page 35.

Note that stimulator waveform is only generated while a sweep is in

Use the pointer to drag the Trigger Marker up or down

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progress.

Mode

There are several possible stimulus waveforms, examples of which are shown in Figure 3–11that are selected using the Mode pop-up menu, Figure 3–10:

• Off. The default setting is to have the stimulator off. No waveform is defined. However a constant output can be defined with the Output Voltage… command, page 42.

38

The profile of the stimulus waveform

Mode pop-up menu selects the stimulus type

Values set by the various controls are displayed above the slider bar

Drag the control handles to reshape the waveform

Range pop-up menu to change the stimulus voltage range

If the external trigger is selected the trigger slope is shown

Figure 3–10 The Stimulator dialog box

• Pulse. A single pulse can be configured during a sweep.

• Multiple. A train of up to 50 identical pulses can be defined within a sweep.

• Double. Two independently defined square pulses can be configured within a sweep.

Use the slider bar controls or text entry button to set values

Click to open a new Stimulator page

Scope Software

• Ramp. A ramp can be configured during the sweep.

• Up & Down. Configures a stimulus waveform that slopes up then down (or down then up) at the same slope.

• Triangle. Configures a triangular waveform, with up to 50 repeats.

• Free Form. Allows a stimulus waveform to be drawn directly, or copy a recorded waveform and modify it as required, see Customized Stimulus Waveforms, page 40.

• External Trigger… this a way to set up triggering conditions for the sweep while in the Stimulator dialog box. See page 43 for further details.


Figure 3–11 Examples of the various types of stimulus waveform

The Time axis settings for the display area depend on the sweep duration set in the Time Base panel, Figure 3–1, page 22. The resolution of the stimulus waveform is always the same as the sampling resolution.

The stimulus waveform can be redefined by reshaping its image in the display area of the dialog box, Figure 3–10, page 38.

Range and Amplitude

The Range pop-up menu, Figure 3–10, page 38, is used to select the range, ±200 mV to ±10 V, over which the amplitude of the stimulus waveform can be adjusted. The Amplitude controls are used to set the exact stimulation voltage within this range. For a double pulse, Ampl A and Ampl B controls let you set the amplitudes of the first and second pulses respectively. For a ramp pulse, Start Ampl and End Ampl controls let you set the amplitudes at the beginning and end of the ramp.

Pulse Multiple Double

Triangle

Up & Down

Free Form

Ramp

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The limits of the Amplitude are independent of Scope input channel settings.

Setting the Controls

The slider bars and Text button ( ) controls can be used to adjust the parameters of the stimulator waveform, Figure 3–10. The shape of the waveform in the display area changes as you change values. The parameters can also be adjusted by dragging the control handles (the little black squares) on the waveform — the pointer changes shape,

40

, when in the right position. The slider bar settings and numerical values change as you alter the shape of the waveform.

The display area of the stimulus waveform can be adjusted by dragging the Amplitude axis tick marks and axis tick tables, in a similar manner to those of the main Scope window, page 49.

Duration, Delay, and Interval

The Duration control is used to set the time for which a pulse lasts. The Duration can be set from zero to the sweep duration. Duration is set in increments of the time taken to record one sample, since the resolution of the stimulus waveform is the same as the sampling resolution. If you change the sweep duration in the Time Base panel, the duration value will be rounded appropriately if required. For a double pulse, Duration A and Duration B controls set the durations of the first and second pulses respectively.

The Delay control defines the period before a the stimulation waveform is commenced. The Delay can be set from zero to the sweep duration.

The Interval control appears only when Multiple or Double modes are chosen, and is used to set the period between the end of one pulse and the beginning of another. The Interval can be set from zero to the sweep duration.

In all cases, any part of the Stimulator waveform falling beyond the duration of the sweep is not physically produced.

Number of Pulses

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If you choose Multiple or Triangle from the Mode pop-up menu, you can specify a number of pulses between 1 and 50. Click the arrows to increment or decrement the number: press and hold the arrows to increase or decrease the number rapidly.

Customized Stimulus Waveforms

If you choose Free Form from the Mode pop-up menu, then most of the parameter controls become inactive, and the drawing tools and copy buttons appear, . The Range pop-up menu works normally,


letting you select the range for the amplitude of the stimulus waveform, from ±200 to ±10 V.

Use the Pencil tool, , to draw freehand curves, and the Line tool, , to draw straight lines. The stimulus waveform can have only one value at any given time, so drawing in an area will replace what previously was there with what you have just drawn. Click the Eraser, , to erase the entire display area.

A recorded waveform can be used as a stimulus or the basis for one. First display the waveform in the Scope window, then click the A or B buttons, , to copy the waveform from Input A or B to the waveform stimulus display area. A copied waveform is scaled vertically to match the set range, but not horizontally, since stimulus resolution must match sampling resolution. Once transferred, the waveform can be edited using the drawing tools. A waveform could also be created in Excel (or other spreadsheet) and then transferred to Scope, page 65, then copied into the Simulator dialog box.

Creating a Stimulus Waveform Library

You can store up to nine different stimulus waveforms in a file. Extra waveforms could be defined using Macros, page 110, if required.

To move to a new stimulus waveform, click the arrows of the Stimulus Page control , Figure 3–10, page 38, or press the left or right arrow keys on the keyboard. Scope will use the stimulus page visible when you click OK to close the dialog box.

Stimulus waveforms are stored, and loaded, as part of the file settings.

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The Stim Panel

Once you have set up stimulation using the Stimulator dialog box, recording and stimulation can be started either through clicking the Start button or through an external trigger event. Settings for the simple stimulus waveforms can be changed using the Stim panel, Figure 3–12, which appears when the Stimulator is on.

Click the arrows to increment or decrement the delay, pulse duration, interval between pulses, and pulse amplitude. To alter the magnitude of

42

Figure 3–12 The Stim Panel

Figure 3–13 Some of the Stim Panel increment dialog boxes

this increment, hold down the Ctrl key ( -key on Macintosh) while clicking the arrows. A dialog box will appear, Figure 3–13, for that control, in which you can set the increment value of that parameter.

Constant Output Voltage

Stimulator waveform voltages are accessed via the outputs connectors on e-corder front panel. You can also generate continuous voltages from these outputs with the Output Voltage… command, in the Setup menu, Figure A–5, page 126, which activates the Stimulator Constant Output dialog box, Figure 3–14.

Scope Software

The Range pop-up menu lets you select the range for the output control, from ±200 to ±10 V. The Level control sets the exact voltage, either positive or negative, within these ranges.

The Stimulator Output

The Stimulator… and Output Voltage… commands can be used together: the stimulus waveform adds to the output voltage, but their sum cannot exceed ±10 V.


Figure 3–15 A constant output voltage together with a pulse from the stimulator

Output dialog box

e-corder units have two output connectors, labelled + and –, which provide a bipolar waveform. That is, if one output gives a positive voltage, the other gives a corresponding negative voltage. Thus a 10 V setting generates a 20 V difference between the two connectors (±10 V with respect to ground).

Stimulator External Trigger

Choosing External Trigger… from the Mode pop-up menu in the Stimulator dialog box, Figure 3–10, page 38, accesses the Stimulator External Trigger dialog box, Figure 3–16. This is a convenient way of

Output + Output –

Range pop-up menu Click for text entry

of output voltage

Click or drag slider bar controls to set output voltage

Figure 3–14 The Stimulator Constant

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configuring the external trigger while Stimulator dialog box is open. Three options are available:

• User, which is equivalent to the User setting, page 35, in the Source pop-up menu of the Sampling Dialog box, Figure 3–8, page 34.

• Off –> On, which is equivalent to the External setting, page 35, in the Source pop-up menu of the Sampling Dialog box, Figure 3–8, page 34. Triggering occurs on the rising edge of a TTL pulse, or on going from open to closed circuit for a contact closure trigger.

• On –> Off, which is equivalent to the External setting, page 35, in the Source pop-up menu of the Sampling Dialog box, Figure 3–8,

44

Figure 3–16 The Stimulator External Trigger dialog box

page 34. Triggering occurs on the falling edge of a TTL pulse, or on going from closed to open circuit for a contact closure trigger.

The slope of an external trigger event is indicated in the Stimulator dialog box Figure 3–8, page 34, by , or . Clicking these icons also accesses the Stimulator External Trigger dialog box, Figure 3–16.

Scope Software

Scope
Software
4
C H A P T E R F O U R
Data Display

Scope allows you great flexibility in displaying data. You can change

the lines, patterns, and colors of the data display. You can resize the

Scope window, change the size of each channel’s display, or overlay

two channels on a page. You can look at a small section of data in

great detail, or overlay data from any selection of pages in a file.

This chapter describes the display options available in Scope, from the

basic settings through to Amplitude axis manipulation, axis labels, and

the Zoom window.

45

46

Figure 4–1 Changing channel height

Data Display AreaRecorded waveforms are displayed in the Scope window in the area bounded by the Amplitude and Time axes. By default, two channels of equal height are displayed, with Input A and Input B showing input channels 1 and 2 of the e-corder, Figure 2–3, page 13. However, it is possible to alter all of these settings to suit your requirements.

Changing Channel Height

Vary the relative heights of the channel display areas by:

1. positioning the pointer over the channel separator handle, , the pointer changes shape, ; then

2. dragging the channel separator to a new position, Figure 4–1.

Double-clicking the handle, , returns the channel displays to equal heights. Note that data is always recorded at full fidelity (resolution), regardless of display size. Channels have a minimum height of about 16 mm on a 75 dpi monitor.

Scope Software

Overlaying Channels

Dragging the channel separator handle, , to the top of the window, or double-clicking it when the channels have the same area, will overlay channels A and B, Figure 4–2. The Amplitude axes for Input A and B are now on the left and right sides of the window respectively. Each axis can be shifted and stretched independently to adjust the display as required, page 48. The channel separator handle, ,

Drag the channel separator to set the height of the channel display

Chapter 4 — Data Display

Figure 4–2 Overlaying channels A and B: top, separate; bottom, overlaid

remains at the top right of the window: double-click it to toggle between overlaid and separate displays.

Displaying a Single Channel

For recording one signal only, first turn a channel off using the Input

To overlay the waveforms, double-click the separator handle or drag it to the top of the window

Input B axis

Input A axis

To display the channels separately, double-click the separator handle or drag it down the window

Horizontal (time) axis

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panels, Figure 3–2, page 25, then:

• overlay the channels (one Amplitude axis will be blank); or

• choose Computed Functions… from the main Display menu, Figure A–7, page 127, to access the Computed Functions dialog box, Figure 6–17, page 95. Select ‘Ch A only’ or ‘Ch B only’, as appropriate, from the Display pop-up menu. The separator handle in the Scope window disappears. Note that if a channel is not displayed, it will still record data unless it is turned off.

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Figure 4–3 The Set Scale pop-up menu and dialog box

The Amplitude AxisThe scale of the (vertical) Amplitude axis of each channel can be independently dragged, stretched, or set through a dialog box for optimum data display. Scale appearance options can be selected from the Set Scale pop-up menu, Figure 4–4:

• Single Sided. Sets the Amplitude axis to display only positive voltage signals. Zero volts is located at the bottom of the display area. Any readings less than zero volts will be off screen (to see them, select the Bipolar option or drag the scale). Note that the Single Sided option is disabled if units conversion is already applied

• Bipolar. This is the default option for a channel, and displays both positive and negative signals to the limits of the channel input range, with zero volts at the centre of the vertical scale. Note that the Bipolar option is disabled if units conversion is already applied

• Set Scale. Enter values for the limits of the Amplitude axis. It works whether units conversion is on or off. When you choose Set Scale…, the Set Scale dialog box for that channel appears, Figure 4–4, allowing the upper and lower limits to be entered for the axis.

• Units Conversion… accesses the Units Conversion dialog box, Figure 3–5, page 29, which allows you to scale or calibrate the raw voltage signal with appropriate units, such as mmHg, kPa. Units conversion is disabled if a channel (or a whole page) has no data.

Note that these settings affect screen appearance only and do not affect signal resolution. Resolution is determined by the range selected for the input channel.

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Click to access the scale pop-up menu

Units of channel (or current page)

Axis label, if any, is shown here


Normal pointer

Dragging pointer

Stretching pointers

Figure 4–4 Pointer changes in the Amplitude axis

The scale of the Amplitude axis can be shifted or stretched or both allowing the signal to be viewed so as to fill the available space. As pointer is moved near to the Amplitude axis it changes appearance, Figure 4–4. Positioned between the axis tick labels the pointer appears as and dragging it will move (offset) the axis up or down. If the pointer is near an axis tick label its will appear as , or , and dragging it the direction indicated will stretch (expand) the axis, while dragging it in the opposite direction will compress the axis.

Dragging or compressing the scale allows you to set the axis to three times the range limit, and stretching allows you to expand the axis up to 20 times.

Double-clicking when the pointer appears as , , or , returns the scale to its normal, unstretched position, with zero at the mid-point of the axis (Bipolar display). Double-clicking again toggles to the Single Sided display, which has zero at the bottom of the axis. Note that this shortcut works on the raw signal values, if units conversion is on, then you may have to drag the scale to adjust the position of the axis zero point.

Axis LabelsSelect Axis Labels… from the Display menu to access the Axis Labels dialog box Figure 4–5. Enter appropriate titles for the Time and the Amplitude axes.

Most of the range of characters found in the usual fonts are available. To get special characters:

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• on Windows computers, use the Character Map accessory program from the Accessories submenu of the Programs menu of the taskbar’s Start button. For the degree sign, °, use Alt+0176, and for the micro symbol, µ, use Alt+0181. Note that the numerals 0176 etc. must be entered using the numeric keypad — not the top row of numbers of the main keyboard.

• on Macintosh use Key Caps if you are unsure about how to get unusual characters. For Ω use Option-Z, for the degree sign, °, use Option-Shift-8, for µ use Option-m, and for ∆ use Option-J.

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Figure 4–5 The Axis labels dialog box

Superscripts and Subscripts

Superscripted and subscripted characters, such as those occurring in Na+ or C2H5OH, can be used in an axis label (and unit definitions):

• to superscript a character or characters, first enter ^, the caret character, by typing Shift+6.

• to subscript a character or characters, first enter §, the section character, by typing Alt+0167 (or use Option-6 on Macintosh).

• to return to normal characters after superscripting or subscripting, enter _, the underscore character, use Shift+hyphen to do this.

The caret (^), section (§), and underscore (_) characters appear only in the text entry boxes, not in the axis labels. Up to twenty characters, including those used to superscript or to subscript, can be entered.

If no label is entered, the normal units appear alone, otherwise the label appears with the units following (in parentheses). If the label and units together are too long to fit in the area allocated in the Scope

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window, they are truncated.

Display SettingsChoose Display Settings from the Display menu, Figure A–7, page 127, to access the Display Settings dialog box, Figure 4–6, which can be used to set the line type, pattern, and color for each signal, the pattern and color of the graticule (the display grid), and whether the background is white or black.


Figure 4–6 The Display Settings dialog box

Figure 4–7 The Color pop-up menu

The Colour Menus

The Color pop-up menus, Figure 4–7, for the graticule and channels let you select a pattern and color.

Background buttons

Waveform buttons

Color pop-up menu, Figure 4–7

Graticule buttons

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Other Controls

The Graticule buttons, , let you choose the form of the display grid: dot graticule (the defaults setting), no graticule, or a line graticule.

The Background buttons, , are used to set the data display area background to white or black. If black is chosen, then black colored signals will be automatically set to white: other colors and patterns are unaffected.

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Figure 4–8 The Overlay Display Settings dialog box

The Waveform buttons, , for each channel are used to display the signal as individual data points (unjoined dots), a continuous trace (the data points are joined by lines), or as a bar graph. The bar graph can be seen more clearly in the Zoom window: the actual data point is located at the top left of each bar.

X–Y and FFT Display Settings

When in X–Y display mode, page 92, or FFT display mode, page 93, choosing Display Settings… from the Display menu will access dialog boxes similar to that shown in Figure 4–6. The Display Settings (FFT) dialog box is identical in most respects Figure 4–6, but applies only to the FFT display. The Display Settings (X–Y) dialog box is also much the same, but applies only to the X–Y plot of Channel A versus Channel B. The settings for each display mode are stored independently of each other, and only apply to the appropriate display mode.

Overlay Display Settings

By default, the signals shown on the active page are displayed in solid colors and the waveforms of overlaid pages are in lighter versions of the same colors. To change the colors and patterns of the overlaid signals choose Overlay Display Settings… from the Display menu, Figure A–7, page 127. The Overlay Display Settings dialog box will then appear, Figure 4–8. The settings for overlay displays are stored independently to those of the active page.

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X–Y and FFT Overlay Display Settings

If Overlay Display Settings… is chosen from the Display menu, Figure A–7, page 127, when using FFT display mode, page 93, then the Overlay Display Settings (FFT) dialog box appears with similar controls to those shown in Figure 4–8. If Overlay Display Settings… is chosen from the Display menu when using X–Y display mode, page 92, then the Overlay Display Settings (X–Y) dialog box appears, with controls similar to those shown in Figure 4–8. The display settings for X–Y or FFT overlays are stored independently of each other, and only apply to the appropriate display mode.

Stimulus Display Settings

The stimulus waveform, page 37, can be recorded directly on an unused Scope input channel by connecting the e-corder output to an appropriate e-corder input. However, it is also possible to display the stimulus waveform without actually recording it, by choosing Overlay Stimulator… from the Display menu, Figure A–7, page 127. which accesses the Overlay Stimulator dialog box, Figure 4–9. The Mode pop-up menu selects the type of the stimulator waveform display:

• Off. This is the default setting. The stimulus waveform is not shown.

• At Top. The stimulus waveform is shown in a separate region at the top of the data display area (Figure 4–10).

• Vert Lines. Vertical lines are overlaid on both channels at start and end of a ramp or pulse, or each of several pulses, in the stimulus waveform. Up & Down and Triangle stimuli are marked at the start and end of stimulation, and at the maxima and minima of the

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waveforms. When using free-form stimuli, this option acts the same as the ‘on both’ option.

• On A. The stimulus waveform is overlaid on input Channel A. The amplitude of the stimulus waveform as a ratio of the Output range is used to scale the stimulus display to the full scale range of input A.

• On B. The stimulus waveform is overlaid on input Channel B. The amplitude of the stimulus waveform as a ratio of the Output range is used to scale the stimulus display to the full scale range of input B.

• On Both. The stimulus waveform is overlaid on both channels. The amplitude of the stimulus waveform as a ratio of the Output range is

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Average page

Blank page

Active page

Page Corner controls

Figure 4–10 The stimulus waveform sown at ‘At Top’ of the data display area

dialog box

used to scale the stimulus display to the full scale range of input A, and input B.

To change the color and pattern of the stimulus waveform use the Color pop-up menu, Figure 4–9.

NavigatingScope stores sweeps of data as if they were pages in a pad of paper.

Stimulus waveform

Figure 4–9 The Overlay Stimulator

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Click on the numbered Page buttons, , along the bottom of the Scope window and the Page Corner controls, at the bottom right of the data display area, to move through multiple pages of a Scope file. The highlighted Page button, ,indicates the page of data currently viewed (the active page). The Average page bottom, , is leftmost, and the last (blank) page button, , at the right: Scope will always have at least these two pages in a file. Pages of data are numbered consecutively as they are recorded, with the blank page remaining at the right. Click the upper corner of the Page Corner controls to move a previous page, and the lower corner to move to the next page — or you can use the left or right arrow keys on the keyboard. Hold down the Ctrl key ( key on Macintosh) while pressing the left or right arrow key to go to the beginning or the end of the file.


Figure 4–11 The Go To Page dialog box

To go to a specific page, click a Page button. If there are too many pages to show all the buttons along the bottom of the window, then and buttons appear at either side: click them to scroll one Page button left or right, or press them to scroll continuously — this doesn’t change the active page, just the range of Page buttons that you can see. Choosing Go To Page… from the Display menu accesses the Go To Page dialog box Figure 4–10, which can be used to nominate a page to view.

Overlaying PagesTo overlay pages of data choose Show Overlay from the Display menu, Figure A–7, page 127. The signals of all pages selected for overlaying can be seen. The Show Overlay command toggles to Hide Overlay which will turn off the overlay display. Note that these commands do not affect which particular pages are overlaid.

To overlay all pages, choose Overlay All from the Display menu, Figure A–7, page 127. The signals of all pages appear with the signal from the active page on top. With default display settings, the signals shown on the active page are in solid colors, and the signals of the other,

Scrolling buttons

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overlaid, pages are in lighter patterns. To remove all pages from the overlay, choose Overlay None from the Display menu.

Using the Page Buttons

The Page buttons along the bottom of the Scope window indicate the status of pages, Figure 4–10. The active page is highlighted ; pages selected for overlaying have taller icons ; pages not selected for overlay have shorter buttons, .

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Figure 4–13 The Page button pop-up menu

Figure 4–12 Page buttons indicate page status

The active page always appears in an overlay, but other pages can be added to or removed from the set of overlaid pages. Ctrl+click ( -click on Macintosh) or double-click a Page button to add/remove a page to/from the overlaid set. Alt+click (Option-click on Macintosh) a Page button to deselect all other pages from the overlaid set. Press the Page button to pop up a menu which duplicates the various overlay and navigation functions, Figure 4–10.

The Scale of Overlaid Pages

When you overlay pages with different vertical ranges, data on other pages is automatically scaled vertically to the range of the active page. However, the time axis is not scaled, so the numbers along the Time axis refer to the times on the active page and not necessarily to overlaid pages, which could have different time bases.

Included in overlay

Average page

Background page

Not included in overlay

Selected page

Blank page

Keyboard shortcuts:Ctrl+click (or -click) or double-click

Ctrl+click (or -click) or double-click

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The Zoom WindowTo magnify a data selection, first drag to select an area of interest in the Scope window, and then choose Zoom Window from the Windows menu, Figure A–8, page 127: the Zoom window appears, Figure 4–14.

Alt+click (or Option-click)


Figure 4–15 The Zoom window with two channels overlaid

You can make a further selection in the data display area of the Zoom window: this automatically zooms in further. However, if the selection contains fewer than four data points along the Time axis, or the vertical selection is less than a few percent of full scale, the Zoom window will appear gray: reselect an area in the Scope window.

Data Display

The Zoom window behaves in many ways like the main Scope window. If the initial data selection covers only one channel, then only one channel is displayed in the Zoom window, and the separator handle is hidden, Figure 4–14. If the selection covers two channels, then the channels are shown overlaid, but double-clicking or dragging the channel separator handle, , will separate them. The channels separate in the main Scope window and overlaid in the Zoom window, and vice versa.

Figure 4–14 The Zoom window

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The scale of the (vertical) Amplitude axis of each channel can be independently dragged, stretched, or set through a dialog box for optimum data display, just as normal. Changing the settings will affect the (vertical) extent of the selection in the Scope window. In particular, if you choose Single Sided or Bipolar from the Scale pop-up menu (or toggle between them by double-clicking) in the Zoom window, then the selection in the Scope window is extended to the top half or the full range of the channel, respectively.

When moving from page to page, the selection area remains the same with regard to the raw data (and will remain in the same relative position in the Scope window).

The Marker, , page 82, from the main Scope window also appears in the Zoom window — moving it onto a signal in one window will update its position in the other, double-clicking it will send it home. Similarly the Page Comment button, page 78, is accessible in the Zoom window.

As you move the pointer across the data display area in the Zoom window, the Waveform Cursor tracks the displayed signals. The time (t) and signal amplitude (on channel A and/or B) at the cursor point are indicated in the Waveform Cursor information display in the Cursor panel. Double-clicking in the Zoom window transfers relevant data to the Data Pad at the point at which you double-clicked, just as it does in the Scope window: the expansion of the waveform in the Zoom window display allows greater accuracy in selecting data points.

The Zoom window can be left open during sampling. First select the area of interest in the Scope window, either on the blank page or on a

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trial signal — the selection area remains in the same relative position in the Scope window when moving between pages. Click the Start button in the Sample panel and then make the Zoom window active. While sampling, you can click the display to clear previous sweeps in superimpose mode, zoom in further on a signal by dragging to make a further selection in the data display area, etc. If the Zoom window is active while sampling, the data display area of Scope window may gray out.


Printing the Zoom Window

When the Zoom window is active, then the Print command in the File menu, Figure A–2, page 126, changes to Print Zoom…, and will print the contents of the Zoom window are printed. The printed page is headed with the window title and the number of the Scope page.

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60
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Scope
Software
5
C H A P T E R F I V E
Working With Files

Scope recordings can be edited, printed, and saved to disk in various

formats. This chapter describes these operations, and such features as

creating a single file summarizing results from many files, and saving

settings to allow easy repetition of an experiment. Other topics covered

include the transfer of data to other applications and the use of page

comments and the Notebook.

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data

Figure 5–2 Selecting data in two channels: left, when overlaid; right, Shift+dragging when the channels are separate

Selecting DataTo select an area of data in one channel, ensure that the channels are separate, position the pointer, and drag to highlight a rectangular area, Figure 5–1. The minimum horizontal extent of any selection in the Scope window is four data points; the minimum vertical selection is a few percent of full scale. The extent of vertical selection affects display in the Zoom window, but will not affect transfer of information to the Data Pad, which uses only the time interval of the selected area to perform calculations.

Selecting Data on Both Channels

To select the same interval of data both channels, first select an area on one channel and then hold down the Shift key and drag to select an area in the other channel — this second selected area will be constrained to have the same time limits as the first. Shift+click in the display area of one of the channels if you want to deselect it.

Figure 5–1 A selection rectangle formed by dragging the pointer over a region of

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Chapter 5 — Working Wit

Figure 5–4 The Set Selection dialog box

If two channels are overlaid, simply drag to create a common selection rectangle over both channels. If you change the channel display from separate to overlaid, you must reselect the area to ensure a common selection rectangle.

Extending the Selection

When dealing with one channel or overlaid channels, Shift+click (or drag) to extend a selection left or right (and vertically) from the point at which you started to drag. When dealing with selections in separate channels, Ctrl+click (or -click on Macintosh) to drag the selection left or right in both channels by the same amount. If you go to the Zoom window and choose Single Sided or Bipolar from the Scale pop-up menu (or toggle between them by double-clicking the vertical axis), then the selection in the Scope window is extended to the top half or the full range of the channel, respectively.

The Selection Miniwindow

To display the precise extent of a selection, choose Selection from the Windows menu to access the Selection miniwindow Figure 5–3. The

Time readings at left and right of selection area.This panel is blank in XY display mode.This panel shows frequency limits of the selection in FFT display mode.

Amplitude readings at Top and Bottom of selection area in Channel A. This panel is blank if there is no signal in Channel A

Figure 5–3 The Selection miniwindow

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Amplitude readings at Top and Bottom of selection area in Channel B. This panel is blank if there is no signal in Channel B

Click to access Set Selection dialog box, Figure 5–4

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The Selection miniwindow ‘floats’ in front of the active window, and has three panels, showing the left and right limits of the selection area, and the amplitude readings at the top and bottom of the selection area for each selected channel. The panels are blank if there is no selection.

Clicking the button accesses the Set Selection dialog box, Figure 5–4, which can be used to exactly define the extent of a selected area. The entered numbers will be adjusted to the values of the nearest data point.

Editing DataThe Cut, Copy, Paste, and Clear commands appear in the Edit menu, Figure A–3, page 126. These actions of these commands can be reversed by use of the Undo command, also in the Edit menu.

When the main Scope window is active, the commands work with whole pages of data:

• Cut removes the active page from the file and places it on the Clipboard.

• Copy places a copy of the active page on the Clipboard.

• Paste adds a page already on the Clipboard to the file before the currently selected page. You can use the Cut and Paste commands to re-order pages (sweeps) within a file.

• Clear removes (deletes) the active page from the file.

A page can be moved between files by cutting or copying to the Clipboard and opening another file, then pasting the page where it is

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required. However, if several pages need to be moved it may be easier to combine two files (see Appending Files, page 70) and then deleting and re-ordering pages as required.

If you need to copy Scope data into another program such as Microsoft Word or Excel, then use the Copy Special… command, page 65.

If the Zoom window is active, the actions of the Cut, Copy, Paste and Clear commands are the same as if the main Scope window was active.


When the Data Pad is active the action of the Cut, Copy, Paste and Clear commands work depends on which tool is selected choose. (If is the active window, then you can copy all of it, or selected rows, to the Clipboard as text.)

The Undo command changes to reflect your last action. For example, if you have just deleted a page from the file by choosing Clear from the Edit menu, then the menu command will change to Undo Clear Data. (Should you choose the command again, it becomes Redo Clear Data.)

Transferring DataTo transfer images from Scope to other software, such as drawing or word processor programs, use the Cut and Copy commands in the Edit menu, Figure A–2, page 126 to place the Scope and Zoom windows on the Clipboard. These are the same pictures (albeit at a lower resolution) you would see if the windows were printed, with title, page comments, etc., but without overlaid pages.

A file, or the contents of the Data Pad, can also be saved as a standard text file able to be opened by any program that can import text, such as a word processor, spreadsheet, or statistics package. (To do this, choose the Save As… menu command from the File menu.)

Special Copying

You can also copy text or graphics to the Clipboard for data transfer using the Copy Special… command, in the Edit menu, Figure A–2, page 126 to access the Copy Scope Window to Clipboard dialog

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box, Figure 5–5. It allows the copying of overlays in pictures (which the Copy command itself does not), and the copying of multiple pages or even an entire file, as text. The command is available only when the Scope, Zoom, or Data Pad window is active.

The dialog box let has three main options:

• As a Picture. If this radio button is on, then the Scope window, including visible overlaid pages, is placed on the Clipboard as a picture, in the ‘enhanced metafile’ graphics format. (This is the same picture you would see if the window were printed.)

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Figure 5–5 The Copy Scope Window to Clipboard dialog box

• As Text. If this radio button is on, then the data from the Scope file is placed on the Clipboard as tab-delimited text. The two checkboxes beneath the button allow you to precede the data with the time and page number if required. With both text checkboxes on, text on the Clipboard would have four columns from left to right: the time, the page number, the data for Channel A, and data for Channel B). Having both times and page numbers might be useful for three-dimensional graphing, for instance. If page overlaying is on, then the data for the entire file will be copied to the Clipboard, regardless of which overlaid pages are visible (if any); if page overlaying is off, only the active page will be copied. If the Append to Clipboard checkbox is ticked, data can be appended to the Clipboard, rather than replacing its contents.

• Data Pad. If this radio button is on, then the data from the Data Pad is placed on or appended to the Clipboard as tab-delimited text. If the Append to Clipboard checkbox is ticked, data can be appended to the Clipboard, rather than replacing its contents

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Similar options are available when you choose Copy Special… with the Zoom or Data Pad windows active. When the Zoom window is active, the Copy Zoom window to Clipboard dialog box appears and the data or picture copied is confined to the selection that the Zoom window displays. When the Data Pad window is active, the Copy Data Pad to Clipboard dialog box appears, but only text copying is possible.


The Clipboard

Whenever you cut or copy data from Scope, the information or a reference to it is stored on the Clipboard. Should you paste from the Clipboard into other software, that program will use the data in its preferred form, as text in a word-processor, or maybe bitmap in a painting program, or an object group in a drawing program. Some programs may be offer you a choice of format.

To see the information stored on the Clipboard, on Windows computers, you need a small accessory program called the Clipboard Viewer. Choose it from the Programs menu of the taskbar’s Start button (under Accessories). It might not be installed, in which case you may want to install it using the Add/Remove Programs control panel, and the original disks or CDs — if you don’t have it, the contents of your Clipboard will remain a mystery until you try to paste them somewhere.

To see the information stored on the Clipboard, on Macintosh computers, use the Show Clipboard command in the Edit menu.

Saving OptionsTo save your results choose Save from the File menu, Figure A–2, page 126. When this is done, an already existing file will have any changes made to it saved to disk. The first time that you save a file, or on any occasion that you choose Save As… from the File menu, the Save As directory dialog box will appear, Figure 5–6.

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You can save files in a number of different formats: Data File; Settings File; text file; Macro file; or Data Pad text file. These formats are discussed in detail in the following sections.

Data File

A Data file format contains all recorded data and settings (including macros). Opening a data file using the Open directory dialog box will open the file, first closing any current file, since Scope can open only one file at a time.

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Figure 5–6 The Save As directory dialog box

Settings File

This format only stores the current settings (that is no data is contained in these files). These include those that affect recording, such as the sampling rate, channel ranges, triggering, and stimulation settings, and those that affect the way the data looks, such as the window size, channel areas, and display settings. Menu configurations and macros, Chapter 7, are also stored as settings. Using settings files, you can build up a series of templates to configure various experiments quickly.

Settings files have a different icon from other Scope files. Double-clicking on a settings file icon automatically load the settings from that

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file into a new untitled Scope file. Opening a settings file using the Open directory dialog box with the Load Settings checkbox selected loads the settings into the current file.

Text File

This format saves data as a tab-delimited text file (page 71) able to be opened by any software that can import text, such as a word processors, spreadsheets, or statistics packages. Each data point occupies a single row of the text file. When opting to save a Scope file as a text file, the Save As Text dialog box appears, Figure 5–7, when you click Save.


Figure 5–7 The Save As Text dialog box

The and checkboxes allow you to add extra preceding columns to the text file containing the time and page number of each data point. With both checkboxes ticked, the resultant text file would have four columns: time, page number, signal value on Input A, and signal value on Input B (if both channels were recorded).

The size of a text file will be much greater than the size of the Scope data file from which it is created, and saving the data of a file as text can be relatively slow: to stop the process, type Ctrl+. , the period character (or -. on Macintosh).

Scope can also import text files, page 71.

Macro File

This format saves any macros (page 110) currently in memory as a separate file, which can be opened by Scope as required. It is useful to save particular groups of macros together.

Macro files have a different icon from other Scope files. Double-clicking on a macro file icon from the Finder will automatically load the macros from that file into a new untitled Scope file. Opening a macro file using the Open directory dialog box (whether or not the Load Settings

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checkbox is on) loads its macros into the current file.

Data Pad Text File

The contents of the Data Pad (page 87) can be saved as a tab-delimited text file able to be opened by word processors, spreadsheets, statistics packages etc. Each row in the Data Pad becomes a row in the text file. Empty columns in the Data Pad are not included in the text file. Titles can be added to the top of each column by using the Data Pad Add Titles command, page 88.

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Figure 5–8 The Open directory dialog box

Appending FilesThis feature allows any Scope data file (or text file in the correct format) to be appended to the end of an already open file in order to produce a single file with the desired contents. By combining this feature with Scope’s ability to cut and paste pages of data in a file or between files, summary files can be created using only those segments of recordings that have significance. Appending a file is an option provided in the Open directory dialog box, Figure 5–8, accessed by choosing Open… from the File menu, Figure A–2, page 126.

Click the checkbox to turn it on. Note that the other checkboxes become disabled — only the settings (including macros) currently in memory are retained. Differences in the settings between the current file and the appended file may result in some scale changes, but the raw data will not be altered. Select the Scope file you wish to append to the currently open file, and click the button to perform the operation. The pages will be added on to the end of the current file. If, however, you append a settings or macro file, its settings are applied.

Select a file to open or append here

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Turn this checkbox on to append the selected file (rather than open it and close the currently open file)


Figure 5–9 The Read Text Options dialog box

Text FilesScope can open text files, or append them to already open files, if they are in the correct format. Choose Open… from the File menu, Figure A–2, page 126, to access the Open directory dialog box, Figure 5–8, and select Text Files from the Files of Type pop-up menu (or Show pop-up menu on Macintosh). After a text file has been selected, the Read Text Options dialog box appears, Figure 5–9.

A text file to be imported into Scope must have at least one column of numbers. Two or more columns of numbers (which must be the same length) would be more typical: each line must consist of items separated by tabs or commas, and ended by a return character. There are several check boxes that allow several variations in the text file:

• Read Titles. When ticked Scope will read in the first line of the file, if its items are non-numeric, as titles for the Time axis, Channel A, and Channel B, in that order.

• Read Time Values. When ticked Scope reads in the first column of numbers as times. There must be a constant increment between lines: a discontinuity is treated as the start of a new page of data. There must be at least four legal lines (data points) o create a page. If this check box is not ticked then no values are red for time and the Time axis will have no units.

• Read Comments. If this checkbox is ticked, then Scope will look for text following the last column of numbers, the first such text for each page will be placed in the Page Comment window for that page.

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Figure 5–10 The Load Text File dialog box

The Seconds, Minutes and Seconds radio buttons allow you to specify the time units of the imported values.

Scope first scans the text file and if it finds an inconsistency there will be an alerts and the file will not be imported. If the text file seems to be in the correct format, and there are more than three columns of data (three columns if times are ignored), the Load Text File dialog box appears, Figure 5–9.

This could be used to import (for example) a Chart text file, which might have as many as sixteen channels of data. Channel A must have data loaded, but Channel B can be left blank (choose None from the pop-up menu).

What Happens to the Text?

When you import text files Scope assumes that signal data has units of

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volts, and the time is in the units chosen in the Read Text Options dialog box, Figure 5–9. Scope pages contain a set number of data points: 256, 512, 640, 1024, 1280, or 2560. When the number of data points in a continuous series is not one of these values, Scope will place extra data onto the next page. The last, partial, page of data will have zero values added for the points needed to make up a full page.

Pasting Text

Text can be pasted directly into Scope from the Clipboard, and goes through the same procedure as imported text. If data includes page numbers (copied using the Copy Special… command, or from a file


Figure 5–11 Typical Page Setup dialog boxes

saved with them), these will be treated as readings. Also, text copied using Copy Special… contains the data as it appears, with all computed functions applied. Scope treats pasted data as if it were raw data, and may apply computed functions to it.

PrintingThere are two menu commands in the File menu, Figure A–2, page 126, concerned with printing: Page Setup… and the Print… command.

Page Setup

When you select the Page Setup… command from the File menu, the Page Setup dialog box will appear, Figure 5–11, to select the paper size, page orientation, etc.

Scope has its own specific options for Page Setup: click the button (or EChem item in the Page Set-up pop-up menu on Macintosh)) to adjust them. The Page Setup Options dialog box will appear, letting you choose the layout of Scope pages on the printed sheet, whether to print in color, and so on.

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Waveform Print Layout

Click the appropriate button to print one, two, three, four, or six Scope pages per printed sheet of paper. The page range specified when printing refers to Scope pages, not pieces of paper produced: printing six pages would, if the button were selected, produce one printed sheet with the six data pages (sweeps)

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Figure 5–12 The Page Setup Options dialog box

on it. This feature will work in conjunction with the Layout options in the Printer Properties dialog box, where these are available.

Windows page setup

Macintosh page setup

Page Set-up pop-up menu

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High-Resolution Printing

Checking prints at the maximum resolution of the selected printer. If you are using a 1200-dpi laser printer, Scope will print with a resolution of 1200 dots per inch. This will result in print of the best possible quality, but, since every data point and connecting line is drawn at full resolution, printing may be slow. Without high-resolution printing, the accuracy of positioning items on the page is limited to the nominal resolution of the computer screen (around 75 dots per inch). This will result in quicker printing and probably be suitable for drafts and routine use. But in most cases you will need high resolution the final copy.


Table 5–1 Printing commands

Print Using Color

Checking enables color printing of your data. You can set up data display colors using the Display Settings dialog boxes, page 51 & 52. Some colors may not be supported by certain color printers, or the colors actually printed may differ from those that appear on a color monitor — you may need to print several pages to establish color compatibility.

The Print Command

If the Page Comment window is active, or the blank page is active in the Scope window, the Print… command in the File menu, Figure A–2, page 126, is disabled. Otherwise the command will appear in various forms depending on which window is active, Table 5–1.

The Print… command (or its variants) accesses the Print dialog box, which will vary in appearance depending on the type of computer and printer that you are using, typical examples are shown in Figure 5–13. The manuals for your printer and computer will explain its use.

Print Command Active Window What PrintsPrint… Scope Page range or current

pagePrint… Zoom Zoom window con-

tentsPrint Data Pad… Data Pad Data Pad contentsPrint Notebook… Notebook Notebook contents

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Scope has a special print option, accessed by clicking the button (or the EChem item in the , on Macintosh computers). This access the Print Options dialog box, Figure 5–14, which is used to ensure that only the active page prints (any range specified in the Print dialog box is overridden). To print a range of pages, you must untick this checkbox.

If the waveforms of overlaid pages are visible, they will be printed.

The Average page is not a numbered page, and will only be printed if it is the active page, , and the checkbox is ticked.

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Figure 5–13 Typical Print dialog boxes

Figure 5–14 The Print Options dialog box

Macintosh Print dialog box

Windows Print dialog box

Print options pop-up menu

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When printing the contents of the Scope or Zoom windows, the Page Layout dialog box appears, Figure 5–15. Use it to adjust the size, location, and proportions of the image. You can also double-click the image to scale it to the maximum size that will fit on the page. If the

checkbox is unchecked, then the image can be reshaped at will. Otherwise the image is scaled in proportion to its original


Figure 5–15

Figure 5–16 Sample print jobs

dimensions (which depend on the Scope or Zoom window settings) or the dimensions set when the checkbox was off. If multiple Scope pages

Drag the image to position it, double-click the image for maximum size

Drag the handle to resize the image

Turn off this checkbox to reshape the image

The Page Layout dialog box

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are being printed on a page, the checkbox will not appear.

The file title, page number, and any page comments, page 78, are included in the printed Scope page. Long comments will reduce the area used for the drawing; very long comments will be truncated. Samples are shown in Figure 5–16.

The Data Pad, page 87, is printed much as it appears on the computer screen but empty columns are not included. The Notebook pages, page 78, are also printed much as they appear on screen.

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Figure 5–17 The Page Comment window

Page CommentsUse Page comments to annotate a particular sweep. Comments must be entered after recording, and can be edited. Use the Notebook, below, to make more general comments.

The Page Comment button, , can be found at the bottom left of the Scope window, and is clicked to access the Page Comment window, Figure 5–17, in which short blocks of text can be entered or viewed for the active page only. Use the keyboard arrow keys to scroll through lengthy comments.

When the Page Comments window of the active page contains comments, the button changes to .

Printing Page Comments

Whenever a Scope page is printed, page comments are printed beneath the pictures. If comments are lengthy, the signals will be displayed in a reduced area when printed (see Figure 5–16). Very lengthy comments will be truncated.

Information on the date the page was modified or the number of

Comment text can be typed in here and edited normally

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The NotebookUse the Notebook tomake general comments about the data recorded in a file. The Notebook is saved as part of the file. (Page comments, above, are used for noting information specific to particular pages.) To use the Notebook, choose Notebook from the Windows menu, Figure A–8, page 127.

pages averaged is given here


Figure 5–18 The Notebook window

The Notebook has a total of eight numbered pages, each of which can contain up to 32 000 characters. Scroll vertically through the contents using the up and down keyboard arrows. Only about the first 1200 characters will print if the Notebook is printed — if necessary copy and paste the text to a word processor to print the contents in full.

The commands Cut, Copy, Paste, and Clear in the Edit menu, Figure A–3, page 126, can be used to edit text. Graphics cannot be pasted into the Notebook. The contents of the Notebook window are saved in both data and settings files. If you apply a settings file containing Notebook information to a data file that also contains Notebook information, then the data file Notebook contents remain intact.

Click to move to next page

Click to move back a page

Click this button to add the date at the insertion point

Click this button to add the time at the insertion point

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Printing the Notebook

To print the contents of the Notebook first open the Notebook and then use the Print Notebook… command in the File menu, Figure A–2, page 126. The Print dialog box, Figure 5–13, page 76, allows you to print the contents of the Notebook, or any selected page range (empty Notebook pages are not printed). The pages are printed out as they appear on screen, but text in excess of about 1200 characters will be truncated — if necessary copy and paste the text to a word processor to print the contents in full.

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6
C H A P T E R S I X
Data Analysis

This chapter discusses the analysis capabilities of Scope:

• signals can be measured directly to give direct or relative, readings, page 82;

• a background page, page 86, can be set to be subtracted from other pages;

• the Data Pad, page 87, calculates and stores statistics about the signals in the different sweeps. You can average the signals on any selection of sweeps and display the results on the Average page.

• the X–Y display mode, page 92, plots a signal from one channel versus the signal on the second channel;

• the FFT display mode, page 93, calculates the power spectrum of a signal; and finally

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• a range of transformations, page 95, can be applied to the raw signals.

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Figure 6–1 Measuring the signal

Signal MeasurementsWhen the pointer is over the data display area, Figure 6–1, it appears as a cross, , but its appearance can be changed, page 104. Waveform Cursors track the signals at the time position of the pointer. The Cursor display panel shows the time at the pointer location and the amplitude of the Waveform Cursors.

The Waveform Cursors move from data point to data point as the pointer is moved (you can see this more clearly in the Zoom window) and cannot provide readings between these points.

Using the Marker

Time at pointer (and Waveform Cursor) position

Amplitudes of the Waveform Cursors

Waveform Cursors

Pointer

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The Marker, , is normally located in its home, at the bottom left of the Scope window, Figure 2–3, page 13. It can be used to set a particular data point as a zero reference point, so that relative measurements can be made, Figure 6–2. To set the reference point, drag the Marker from its home onto the channel of interest; and release it: it will lock onto the signal. Alt+drag (Option-drag on Macintosh) to position the Marker independently of the signal. Use the Waveform Cursor display in the Cursor panel to help to select a data point. If you need finer control to position the Marker, use the Zoom window: the Marker also work in this window and can more easily be assigned to a particular data point.

Chapter 6 — Data Analysi

Figure 6–2 Measurements relative to the Marker

When moving between pages, the Marker will remain at the same time position: if locked to the signal, it will lock to the new signal at that time; if independent, it will remain static. Double-clicking the Marker or clicking its home box at the bottom left of the Scope (or Zoom) window sends it back home.

Once the Marker is in position, measurements relative to it are given in the Cursor panel, Figure 6–2. The ‘∆’ symbol before a value, for example, , indicates that it is a relative reading to the Marker.

Switching between X–Y, FFT, and normal Scope display modes will send the Marker home.

Setting and Removing Baselines

Time at pointer position relative to Marker. Note the ∆ symbol

Signal amplitude at the Waveform Cursor relative to Marker. Note the ∆ symbol

MarkerAbsolute signal amplitude at the Waveform Cursor

Cursor display panel

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The Marker is also used for setting relative amplitude measurements relative to an arbitrary baseline. Place the Marker at on the channel of interest. Then Ctrl+click (or -click on Macintosh) and drag from the Marker home area, or the Marker itself, to create a duplicate Marker. The two Marker positions define a baseline shown as a dotted line, Figure 6–3. Use Ctrl+Alt+click (or -Option-click on Macintosh) and drag to locate the second Marker at a position off the signal.

The value along the baseline is set at zero: the Waveform Cursor display in the Cursor panel shows the absolute time, and the amplitude of the waveform in that channel relative to the baseline.

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Figure 6–3 Setting a baseline

Note that the baseline is set for a particular channel on a particular page of data. When moving between pages, the baseline may move considerably if locked to the signal; if independent, it will remain static. Removing one Marker removes both Markers, and the baseline. Attempting to set a vertical or near-vertical slope will also remove the baseline and send the Marker home.

You cannot duplicate the Marker or set a baseline when in the X–Y display mode.

The Marker Miniwindow

To display the exact Marker position(s) choose Marker from the Windows menu to access the Marker miniwindow Figure 6–4. The Marker miniwindow ‘floats’ in front of the active window and is divided

Time at pointer position

Amplitude at Waveform Cursor position relative to baseline

Marker

Pointer

Duplicate Marker

BaselineWaveform cursor

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into three panels, showing the channel in which the Marker is active, and the time and amplitude readings at the Marker position, and the duplicate Marker position if a baseline is set. If the Marker is inactive, the two lower panels are blank and the top panel displays ‘Off’.

Clicking the Set… button accesses the Set Marker Position dialog box (Figure 6–5), which allows you to alter or define the Marker or baseline position by typing values into the text entry boxes.

In the Set Marker Position dialog box, clicking the Off radio button turns the Marker (or baseline set with the Marker and its duplicate) off, and clicking the Chan A or Chan B radio buttons selects the channel in


Figure 6–6 The Set Marker Position dialog box for the X–Y display mode

The channel in which the Marker is active. This panel shows ‘On’, in the XY display mode.

Time and amplitude and readings at the Marker position in the active channel

Time and amplitude and readings at the duplicate Marker position. This panel will be blank if the duplicate Marker is not present.

Click to access the Set Marker Position dialog box, Figure 6–5

Amplitude at Marker position

Time at Marker position

Select Marker channel

Position Marker on signal

Figure 6–4 The Marker miniwindow

Figure 6–5 The Set Marker Position dialog box

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which the Marker will appear. If the checkbox is ticked, the Marker will be set on the signal amplitude at the selected time, while the text entry box for Marker amplitude position is disabled. If the checkbox is off, the Marker is can be located independently of the signal by entering values in the Marker 1 or Marker 2 text entry boxes. Entering values into both Marker 1 and Marker 2 text entry boxes will create a baseline.

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In the X–Y display mode, page 92, the Marker miniwindow, Figure 6–4, shows no time readings if the Marker is set independently of the signal, and the Set Marker Position dialog box, Figure 6–6, can be used used to position the Marker independently of the signal.

Background SubtractionThe signal(s) on a background page is/are subtracted from the signal(s) of similar pages in a file — that is, those with the same settings of time base, input range, and units. This can be used for non-linear baseline subtraction, or can be used to enhance a small signal with a noisy background.

Go to the page selected to be the background, and choose the Set Background command from the Display menu, Figure A–7, page 127. The Page button for a background page has the page number underlined, . The signal on the background page is subtracted from the signal on the active page, so viewing the background page will now show a zero signal. The Display menu commands Subtract Background and Clear Background in the Display menu will be enabled while a background page is in memory.

The Subtract Background command toggles with the Don’t Subtract Background command in the Display menu, Figure A–7, page 127. Both leave the background page in memory, but will subtract it or not

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subtract it, respectively, from signals in the open file, to compare waveforms before and after subtraction. Choosing Clear Background from the Display menu clears the background page from memory, and all pages will show unsubtracted signals. Once a background page has been set, Scope stores it in memory, even if the file is closed. You can then open another file and use the old background.


Figure 6–7 The Data Pad window and pup-up menu

The Data PadTo display the Data Pad, Figure 6–7, select Data Pad from the Windows menu. The Data Pad is used to analyze signals, and acts like a small spreadsheet with up to 32 columns and 32 000 rows, with each row having a maximum of 255 characters per cell, and a total of 2000 characters per row over the 32 columns. Its contents can be saved as a text file or copied in whole or part to the Clipboard for export to other software.

Information on the current selection or active point (the last point clicked in the data display area) is displayed in the row immediately beneath the column headings. As data are added to the Data Pad, new rows of values are created below existing rows in the data area. Each cell contains only one entry, the value added to the Data Pad at the time the calculation for its column was made.

If the Row button, , is highlighted (click on it) the pointer changes to a heavy cross, , over the data area. Click to select a row, drag or Shift+click to select contiguous rows, or Ctrl+click ( -click on Macintosh) to select or deselect rows individually; the data can then be

Data Pad pop-up menu

Double click a column heading to access the Data Pad Setup dialog box, Figure 6–8

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Cell button Data on the current selectionColumn

headings. Drag a heading to create a miniwindow, Figure 6–9, page 90

Row button

Recorded data

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cleared, or cut or copied to the Clipboard as tab-delimited text (Edit menu). If the Cell button, , is clicked, the pointer changes to an I-beam, , over the data area, and text in each cell can be edited.

The Data Pad pop-up menu, Figure 6–7, provides a series of commands:

• Add Blank Lines, which inserts blank lines in Data Pad, and is useful to separate block of parameters.

• Add Titles, which inserts the full current column headings as spread over three lines. (Superscripts and subscripts in column headings are converted to plain text when added to the Data Pad.)

• Clear Data Pad on New, clears the Data Pad contents when a new file is created. A tick appears beside this menu command when it is active (it applies only to the current file).

• Auto Add, the Data Pad is updated for every sweep as it is recorded, whether single, multiple, average, or superimposed, and whether or not the sweep is on a new page. A tick appears beside this menu command when it is active (it applies only to the current file).

The width of columns can be altered by positioning the pointer on the heavy dividing line between column headings, so that it changes to , the resizing pointer, then dragging until the column is the desired width.

Adding Data to the Data Pad

To extract parameters from a selected region of the into the Data Pad, choose Add to Data Pad from the Windows menu. If there is no

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selection, parameters at the active point are transferred — you can also double-click at a point of the signal to make it the active point and transfer parameters to the Data Pad, all in the one action. The parameters entered in the Data Pad are determined using the Data Pad Column Setup dialog box, Figure 6–8. By default, the first two columns are set to record the mean of the selection in a channel, or the value of the signal at the position of the active point if no selection has been made.


Figure 6–8 The Data Pad Column Setup dialog box

Setting Up the Columns

Data Pad columns can be configured to contain different information with the Data Pad Column Setup dialog box, Figure 6–8, accessed by clicking a Data Pad column heading, Figure 6–7.

To move to the dialog boxes of adjacent columns click the arrows at the top left of the dialog box, or press the right or left arrow keys on the keyboard. Data Pad functions are grouped into general categories:

• Off turns the column off so that no entries will be made.

• General Statistics offers calculations of the mean, standard deviation, standard error of the mean, and various integrals of the selection. The value of the largest or smallest data points in the selection (or the difference between them), the times at which they were recorded, and the number of data points in the selection, can also be obtained.

Click arrows to move from column to column

Activate a Miniwindow, Figure 6–9

General category

Specific function

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An entry in the Data Pad will only be made for this channel

A description of the Data Pad function is given

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Drag the title bar to position the miniwindow

Double click to open the Data Pad Column Setup dialog, Figure 6–8

Figure 6–9 A Data Pad Value miniwindow

• Selection Information, if there is a selection, provides functions for start time, end time, or duration of the selection, current page number, and the date or time when the page was recorded.

• Cursor functions give the time or value at the active point, if there is one, or does nothing if there is a selection.

• Slope (first derivative) functions include maximum and minimum slope of a selected area of the signal, the average slope of a selection, or the slope at the active point, see page 142.

There are three radio buttons, Figure 6–8, that indicate the conditions for adding entries to the Data Pad:

• When Any Channel is Selected, information will be recorded about the channel selected in the Channel pop-up menu no matter on what channel the selection occurs. For example if you have selected an region on Channel A, information on Channel B could still be added to the Data Pad.

• Only When Channel is Selected, information about the channel is added to the Data Pad for that column only if the selected region of the signal is on that.

• From First Channel Selected, information is recorded only about Channel A if both channels are selected.

The Compact Data checkbox works in conjunction with the middle radio button: if you select data from different channels at different intervals after the same stimulus, for instance, it will place all the data on the same line in the Data Pad (if the checkbox is off, then each entry will be recorded on a new line).

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The Data Pad is useful for quickly collecting statistical information about your signals and it can be displayed as background window that will be updated as new entries are made. In addition, Data Pad miniwindows, Figure 6–9, can be created to display the current values of statistics or measurements: tick the Miniwindow checkbox,

, in the Data Pad Column Setup dialog box, Figure 6–8, or drag the column heading to tear it off the Data Pad window, Figure 6–7, page 87. These miniwindows float above the main Scope window.


Figure 6–10 An Average page display, showing the mean signal from sweeps 2 and 4

NoteIf you apply units conversion to the

Printing

When the Data Pad window is active, then the Print command in the File menu changes to Print Data Pad…, and will print the contents of this Data Pad, across several pages if it is very wide.

The Average PageThe Average page displays the mean of the waveforms of a number of pages, Figure 6–10. Display the Average page by clicking its Page button, , in the main Scope (page 13, 92 & 93) or Zoom (page 57), windows, or by choosing Go to Page… from the Display menu, Figure A–7, page 127, and going to page 0 (zero). The pages selected for averaging are the same set as is used for overlays, see Overlaying Pages, page 55. In addition the pages used for averaging must have the:

• same number of data points;

• same sampling rate; and

• same set units (if units conversion has been used)

as the first (leftmost) page in the overlay. If the Average page is active, the footnote in the Page Comments window (page 78), indicates how many pages are being averaged. Pages can be added to, or taken from, the overlay by Ctrl+clicking ( -clicking on Macintosh) or double-clicking their Page buttons, page 55.

The range displayed in the Amplitude axis for the Average page is the mean of the ranges for the pages averaged. Overlaid waveforms are

Average page, the same units will be applied to all pages in the overlay.

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Overlay of sweep 2

Overlay of sweep 4

Mean signal shown on Average page

Average page

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Figure 6–12 The X–Y display

drawn scaled to this average range. FFT and X–Y displays (page 92 & 93) can also be averaged: Scope calculates the plots for each page, and then averages the values together, that is an FFT of each sweep is calculated and these FFTs are averaged.

The Average page button, , is not numbered. Thus the Average page can only be printed if it is the active page and the checkbox in the Print dialog box is on, page 75.

The X–Y DisplayIf X–Y is selected from the Display pop-up menu, Figure 6–11, then the X–Y display area shows a graph of Channel A data, along the vertical axis, versus Channel B data, along the horizontal axis, Figure 6–12. No graph appears if only a single channel is present.

Select the type and pattern or color for the signal with the Display Settings command located in the Display menu, Figure A–7, page 127. This accesses the Display Settings (X–Y) dialog box, page 52.

Waveform Cursor

Pointer

Input A scale pop-up menu

Figure 6–11 The Display pop-up menu

Access FFT options, Figure 6–14

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Input B axis

Input A axis

Input B scale pop-up menu

XY display mode selected


Figure 6–13 The FFT display. The top channel has a logarithmic (dB) axis, the bottom one a linear axis

The Waveform Cursor tracks the X–Y signal at the position closest to the pointer. The Cursor panel shows the time at the pointer location and the and signal values at that time. If it is difficult to measure a particular section if the signal overlaps itself, then select the area and use the Zoom window.

The FFT DisplayIf FFT is chosen from the Display pop-up menu, Figure 6–11, then the data display area for each channel shows the power spectrum of the data, Figure 6–13. Formally, this is the modulus of the amplitude spectrum, and is calculated using a FFT, Fast Fourier Transform, method to convert data from time to frequency domain.

The FFT display mode shows the intensity of the frequency components in the raw signal, see Fast Fourier Transforms, page 137, for details. The horizontal axis displays frequency, in units of Hz. The type and pattern or color for the waveform is chosen in the Display Settings (FFT) dialog box, page 52, Figure 6–13 shows a bar graph display.

The Waveform Cursor tracks the FFT waveform following the pointer and the Cursor panel shows the frequency, f, and amplitude of the FFT waveforms.

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The FFT horizontal axis has units of frequency, Hz

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The FFT Options dialog box for setting FFT windowing functions

when the FFT display has been chosen

Figure 6–16 The 0dB Reference Level dialog box

FFT Options

The FFT Options… command in the Display pop-up menu, Figure 6–11, accesses the FFT Options dialog box, Figure 6–14, which can be used to select a FFT windowing function.

The FFT method assumes that samples represent an integral number of cycles of a periodic waveform. Windowing functions are applied to correct for any inaccuracies that arise because of that assumption. They work by reducing the importance of data at the edges of the ‘window’ (the selection of data points used by the FFT). You may need to try several window functions before making the best choice — however, in most cases the effect of the different window functions is small. See Fast Fourier Transforms, page 137 for more details.

Figure 6–14

Figure 6–15 The Scale pop-up menu

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Units control

Click to set the 0 dB reference level, Figure 6–16

Click to set a log (dB) axis for the FFT display, and toggle to Linear scale.


Function pop-up menu, Figure 6–21

Math pop-up menu, Figure 6–20

Ordering of computed functions

Function controls

Figure 6–17 The Computed Functions dialog box

Vertical Scale

When the FFT display mode is chosen the Scale pop-up menu, Figure 6–15, offers extra options for scaling the vertical axis:

• Log Scale. Produces a vertical axis with a logarithmic display, and units of decibels (dB), showing the relative attenuation with respect to a reference level (0 dB). Decibels are a ratio scale, so a measurement of zero means a ratio of 1:1 relative to the reference level. This command toggles with Linear Scale.

• Reference Level. This command accesses the Reference Level dialog box, Figure 6–16, to set the 0 dB level for the Log Scale
display. By default, it is set to 0.775 (the square root of 0.6), a common reference.
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Computed FunctionsScope’s computed functions can be applied singly or in combination. Scope always records a raw signal raw to which the computed functions are applied. The functions can be selected before or after recording, and turned off again to restore the raw signals.

Display pop-up menu, Figure 6–18

Units order of magnitude control for math

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Figure 6–18 The (computed function) Display pop-up menu

The Computed Functions dialog box, Figure 6–17, is accessed via the Computed Functions… command in the Display menu, Figure A–7, page 127. Functions for each channel can be configured independently. The Display pop-up menu of the dialog box, Figure 6–17, can also be used to combine the two channels in various ways. The function or functions chosen will apply to all pages in the file.

Sampling Rate

Computed functions do not affect sampling rates, but may affect the delay between consecutive sweeps. The speed of computations applied to data depends on the speed of the computer, so a slower computer will give a longer delay between sweeps. If this proves to be a problem, apply computed functions after sampling.

UnitsSome functions will change the (vertical axis) units of displayed data. This is quite straightforward when the units are volts, although units set with units conversion might change considerably.

When multiplying two signals together, the resulting units are the product of the original signals’ units. When adding or subtracting signals, the units must be the same for both signals, or no operation can be performed. The units of an integrated signal are the product of the signal units with the time units of the time axis; units of a differentiated signal are the units of the raw signal divided by the time units of the time axis.

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Display Functions

The Display pop-up menu, Figure 6–18, at the top of the dialog box, Figure 6–17, allows various display options in the main Scope window:

• Ch A and B, the signals of both channels are displayed.

• Ch A Only, or Ch B Only, displays only the signal of that channel. The second channel is hidden but is not turned off — it may still be used to collect data, and viewed again at a later stage.


• Ch A + B displays the sum of the two channels. The units of the signals must be the same for both signals, or no operation can be performed.

• Ch A – B, or Ch A – B displays the difference signal of the two channels. The units of the raw signals must be the same for both signals, or no operation can be performed.

• Ch A * B displays the product signal of the two channels. The units of the raw signals must be the same for both signals, or no operation can be performed. The units of the product signal are the product of the units of the raw signals.

Channel Functions

The dialog box has one panel for Channel A and one for Channel B, in which functions for the two channels can be set independently. If multiple functions are applied, their order is from the top to the bottom of the panel: the waveform is first smoothed, then shifted, and so on. The display panel at the bottom of the dialog box indicates this order (and the display settings, as well).

Smooth

Data can be smoothed to remove unwanted high frequencies or noise, in the signal, Figure 6–19. If the control is set to zero, then smoothing is off (the default); the larger the number entered, the greater the smoothing. Click the arrows to increment the degree of smoothing; press and hold the arrows to increase or decrease the number rapidly; or type a value, ‘n’ from 1 to 50, in the text box

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to set the degree of smoothing. Within ‘n’ points of the start and end of the sweep it is not possible to use ‘n’ data points for smoothing and so degree of smoothing will decrease in these regions, Details of the smoothing algorithm can be found on page 140.

Shift

The Shift control moves a waveform horizontally, that is with respect to time. If the control is set to zero then shifting is off (the default). Click the arrows to change the number; press the arrows to increase or decrease the number rapidly; or type a value in the text box directly. Positive values shift data to the right, negative to the left, by an

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Figure 6–20 The Math pop-up menu

Figure 6–19 Typical effects of smoothing a signal

integral number of data points. The maximum value for a shift is ±2560 (the maximum number of samples per sweep) — large numbers can be used to hide most the signal for display purposes.

Math

The Math pop-up menu, Figure 6–20, lets you apply some simple arithmetic to the signal:

• None is the default setting and no arithmetic function is applied to the signal.

• Add or Subtract a constant value to the signal. The value can be

Original signal with no smoothing

Smooth value of 1

Smooth value of 2

Smooth value of 4

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up to ±30 000, and can have up to 12 characters. This value is assumed to have units the same as the signal, but you can use the arrows in the control to alter the unit order of magnitude.

• Multiply or Divide the signal by a number up to ±30 000, and 12 characters long. You cannot enter zero.

• Invert is equivalent to multiplying the signal by –1, effectively reversing its polarity. Thus positive signal values become negative, and vice-versa.

• Abs displays the absolute value of a signal; that is, negative values are displayed as positive.


Figure 6–21 The Function pop-up menu

Function

The Function pop-up menu, Figure 6–21, can be used to transform that the signal:

• None is the default setting and no function is applied to the signal.

• Reciprocal displays the reciprocal of the signal, that is, 1⁄x for any data point of value x. Zero signal values would become infinite are displayed as off scale.

• Square displays the square of the signal, that is, x2 for any data point of value x.

• Integrate displays the area under the signal, calculated as the sum of the data points multiplied by the sample interval. The integral of a negative signal is also negative. See page 140 for more details.

• Differentiate. This function gives the first-order derivative of the signal with respect to time. See page 141 for more details. The Differentiate functions are particularly sensitive to noise, and it is often useful to combine this function with signal smoothing, page 97.

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7
C H A P T E R S E V E N
Customizing & Automating

Scope can be extensively customised and automated, to increase its

convenience and ease of use. Menus and menu commands can be

locked, hidden, or altered, page 105, and control panels can be

relocated, page 107. Macros, page 110, can be created to speed up

and to automate complex tasks, and stored in any menu in a file; and

new menus can be created. On Macintosh computers there is limited

AppleScript support, page 120.

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PreferencesThe various options in the display settings and recording controls allow basic customizing of Scope. You can also choose to lock, hide, or alter controls, menus, and menu commands (and their keyboard shortcuts). This is useful in simplifying Scope for teaching purposes. The Preferences submenu, Figure A–4, page 126, in the Edit menu contains the menu commands:

• Options…, below

• Menus…, page 105,

• Controls…, page 106,

• Start-Up…, page 107,

• Hardware Start-Up…, page 109, and

• External Trigger…, page 109,

to manage particular aspects of Scope performance and display, and which are discussed in the sections below.

Options

Selecting the Options… command from the Preferences submenu, Figure A–4, page 126, of the Edit menu, accesses the Scope Options dialog box Figure 7–1. Double-clicking the Rate/Time display in Time Base control panel, Figure 3–1, page 22, also displays the dialog box.

The Scope Options dialog box controls various display and recording

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settings. There are three main panels with controls which affect general settings, the appearance of the waveform cursor, and the appearance of the Time Base control panel.

General Behavior

Four checkboxes can be set to tailor various aspects of the Scope software behavior:

• Keep Partial Data. When this checkbox is ticked, the portion of signal obtained during an interrupted sweep is kept as a partial page; the remainder of the page is filled with a zero signal. If the

Chapter 7 — Customizing

Figure 7–2 The Display pop-up menu

Figure 7–1 The Scope Options dialog box

checkbox is unticked (the default setting), then partial sweeps of data are discarded.

• Show Display Control. If this checkbox is not ticked, the Display pop-up menu is hidden, Figure 7–2. This prevents unwanted changes to the display mode. Make sure that the display setting is correctly set before you hide the control.

• Always Sample on Empty Page. By default, recording starts on the blank page at the end (right) of the current file. If this checkbox is not ticked, then for single, repetitive, averaged, or superimposed sweeps, recording starts on the active page, overwriting any data already there; in addition, you cannot start multiple sweeps when the active page contains data, but must move to the blank page.

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• Stimulator Independent of Sampling Rate. If the checkbox is ticked (the default setting), then the stimulus waveform will maintain its settings if the sweep time base is changed. When this checkbox is turned off, the time base of the stimulus waveform automatically rescaled when the sampling rate is changed, so that it remains the

Display pop-up menu

Hidden Display pop-up menu

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Figure 7–3 The three Time Base panel configurations, with the same sampling rate

same relative to the sweep. Note that Stimulator range is always set independently and is not dependent on the Input range selected for the sweep.

Waveform Cursor

The Waveform Cursor control, , allows a choice of cursor shape. Click on a shape to select it: it is then highlighted with a heavy border.

Time Base

The Time Base radio buttons set which two variables are used to control sampling, page 22, by changing the Time Base control panel, Figure 7–1. By default, the Time per Sweep radio button is on. Click one of the radio buttons to select that setting:

• Time per Sweep. The time taken for each sweep is set through the Time/Freq pop-up menu, the number of samples per sweep is set through the Samples pop-up menu, and the Rate/Time display shows sampling frequency.

• Time per Div. The time taken for each division of a sweep is set through the Time/Freq pop-up menu, the number of samples per division is set through the Samples pop-up menu, and the Rate/Time display just shows ‘/Div’. This gives the same range of sampling rates as the default setting, since there are always 12.8 divisions per sweep (see Table 3–1).

• Sampling Frequency. The sampling rate is set directly from the Time/Freq pop-up menu, the number of samples per sweep is set

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through the Samples pop-up menu, and the Rate/ Time display shows the time taken for each sample. This allows freer choice and a greater range of times per sweep, as shown in Table 3–2.

Time per Sweep Time per Div Sampling Frequency

Rate/Time display


Figure 7–4 The Menus dialog box, Note that the Crtl key of a Windows computer is the Cmd, -key on Macintosh

Menus

Six of the Scope menus (File, Edit, Setup, Display, Windows, Macro) and their commands can be modified from the default settings by using the Menus dialog box, Figure 7–4, which appears on selecting the Menus… command from the Preferences submenu of the Edit menu. The dialog box will initially display the File menu: click the arrows, , or press the right or left arrow keys on the keyboard, to move to adjacent menus. The Help menu cannot be edited, but other menus, or menu commands can be hidden or locked.

Long menus will have a ▼ button at their bases: click it (or press the keyboard down arrow key) to move down through the menu, then click the ▲ button that appears at the top of the menu (or press the up arrow key) if you need to move back up again. By default, the menu title and all items within the menu will have a adjacent tick icon, , and all menu commands will have an open padlock icon, , beside them.

Clicking a tick, , will toggle it to a cross, , and hide the menu or command, which will not appear when you return to the main Scope window. Keyboard shortcuts for hidden commands are deactivated. Clicking a cross will toggle it to a tick.

Click to move to adjacent menus Cmd, key on Macintosh

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▼ ReferKeyboard Shortcuts, page 129

Clicking an open padlock, , toggles it to a closed padlock, , and locks the menu command beside it. The command still appears in the menu, but if it is selected, or its keyboard shortcut entered, then an alert notifies the user that it is locked and cannot be used. Clicking a closed padlock toggles it to unlocked.

Keyboard Shortcuts

Keyboard shortcuts for menu commands can be added or changed. Click a menu command to select it: it highlights and the Ctrl Key area (Cmd, , Key area on Macintosh) of the dialog box becomes undimmed. If the menu command already has a keyboard shortcut, the letter key appears selected in the text entry box, and you can either change it, or delete it so that no keyboard shortcut is available. Type a single lower-case letter or number in the text entry box (letters are automatically capitalized; invalid characters will be rejected) to assign a keyboard shortcut.

If you choose a character already in use, an alert box will warn you of the fact and tell you where it is assigned. If you choose the character anyway, your choice overrides any previous assignment.

Controls

The Controls… command from the Preferences submenu of the Edit menu, accesses the Control Options dialog box, Figure 7–5. Use it to modify the display of the various Scope control panels. By default, all items have a tick, , and an , icon to their left indicating that control panel is visible and will appear behind the Scope window in

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case of overlap.

Clicking a tick, , will toggle it to a cross, , and hide the panel named beside it when you return to the main Scope window. Clicking a cross, , to toggle to a tick, , and show the hidden item.

Click the icon, it toggles to , and that panel will appear in front of the main Scope window. You can also Alt+click (Option-click on Macintosh) directly on a panel title to toggle it to the front or back of the main Scope window. The horizontal and vertical spaces can be hidden, but always remain behind all other Scope panels and windows.


Figure 7–6 The Start-Up Settings dialog box

Figure 7–5 The Control Options dialog box

If the Stimulator is set up to deliver stimulus waveforms other than free-form, the Stim panel, page 41, replaces the e-corder panel when the Stimulator is on. The control in the dialog box also changes its name depending on what is visible on screen; settings are retained, though.

Moving Control Panels

The panels named in the Control Options dialog box can be repositioned by using Shift+drag on their title. Vertical and horizontal spaces have no title, and can be Shift+dragged from any point.

Start-UpSettings are of two sorts: those that affect recording, such as sampling rate, channel ranges, triggering, and stimulation functions; and those that affect the way the data looks, such as the window size, channel

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areas, display settings, and menu configuration. To save or clear customized settings, select the Start-Up… command from the Preferences submenu, Figure A–4, page 126, of the Edit menu: the Start-Up Settings dialog box appears, Figure 7–6.

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Figure 7–7 The Special Access dialog box

Clicking the button saves all current settings in the Scope StartUp file in the System folder in the eDAQ folder, so that they are used each time Scope starts up. Clicking the button clears any settings stored in the Scope StartUp file: when Scope next starts up, it will use its factory default settings. Note that you must quit and restart Scope to apply the new start-up settings.

If you hold down the Ctrl key ( key on Macintosh) as you start the Scope software, then any customized start-up settings are bypassed, and Scope opens using the factory default settings.

It is also possible to always start Scope in Analysis mode, page 109 & 123.

Special AccessIf access to dialog boxes has been blocked (because the Edit menu or its relevant commands have been hidden or locked, page 105) use the Special Access dialog box, Figure 7–7, which appears on typing Ctrl+\, the backslash character ( -\ on Macintosh).

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Clicking the button accesses the Menus dialog box, Figure 7–4, which can be used to show hidden menus, and unlock menu commands, if required.

Clicking the button accesses the Start-Up Settings dialog box, letting you save the current settings in the file (including menu layouts and so on) as those Scope will use when it starts up. This is useful when you use Scope for routine work requiring the same settings day after day. It also means that quitting and restarting Scope will not face the user with a Scope file that could have quite different settings, and none of the safeguards you may have set up.


Figure 7–8 The Special Access dialog box

Clicking the button accesses the Save As directory dialog box, which allows you the complete range of options in saving a Scope file. It is useful where you have previously used the menu editor, page 105, to disable the ability to save a file, and then want to save this configuration as a Settings file.

Hardware Start-Up

The Hardware Start-Up command in the Edit>Preferences submenu, Figure A–4, page 126, accesses the Hardware Start-Up dialog box, Figure 7–8. Use it to bypass hardware initialization if you are using Scope on a computer without an e-corder attached, for example to review and analyze existing data files — the Hardware Not Found dialog box will not appear, Figure 1–2, page 4.

This is equivalent to renaming Scope as ‘Analysis Scope’, see page 123.

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External Trigger

The External Trigger command in the Edit>Preferences submenu, Figure A–4, page 126, accesses the External Trigger Options dialog box, Figure 7–9, which configures the external Trigger of the e-corder unit to respond to a TTL (voltage level) signal or to a contact closure (open versus closed circuit). See the e-corder manual for more information. (The External trigger can be selected using the Sampling dialog box, Figure 3–8, page 34.)

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Figure 7–9 The External Trigger Options dialog box

MacrosMacros are used to repeat a set of commands and are commonly used to automate recording and analysis, or like settings files, to quickly reconfigure the appearance and recording parameters of Scope. They record the results of your actions then reproduce these steps when replayed. They are useful wherever you need to perform a repetitive series of operations.

Macros can record any Scope operation: setting dialog box and window controls; changing the display format; sampling; copying waveform data to the Data Pad; saving data as a new file; printing the Zoom window display of selected data; etc.

Macros work by recording the simplest interpretation of your actions, not the individual keystrokes and mouse clicks. For example if you open a dialog box while running a macro, then readjust the same setting

TTL configuration for external trigger

Contact closure configuration for external trigger

Flashes red for TTL high, or contact closed

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several times during, only the final settings used in the macro.

Keep a written record of the steps involved in your macros because, once saved, macros cannot be edited. Macros may also be incompatible between different versions of Scope. Writing the macro steps down before actually recording will help when constructing complex macros.

Macros are saved with data or settings files: when the file is saved, all currently available macros are saved with it, becoming part of the file. When you open a Scope data, settings, or macro file, any macros in that file are loaded into memory. The Open directory dialog box, has a


Figure 7–10 The Add Macro to Menu dialog box

Discard Existing Macros checkbox. If this is on, macros currently in memory are discarded when the new file is opened, and any macros in the new file replace the previous set. If the checkbox is off, macros accumulate in memory as you open files until you quit and restart Scope, or delete the macros.

Macros can also be saved as a separate Macros file, with the Save As command.

Recording a Macro

Choose Start Recording from the Macro menu, the menu command then toggles to Stop Recording…. When a macro is being recorded, for the most part Scope remembers rather than executes operations, but changing channel ranges or turning channels off, for example, are done as you record. During the process, the Progress indicator changes in the e-corder or Stim panel, and the message ‘Recording Macro…’ is displayed, , in the e-corder panel. Perform all actions to be recorded, then choose Stop Recording… from the Macro menu. Once recording stops, the Add Macro to Menu dialog box appears, Figure 7–10.

The button allows you to choose the menu in which your macro will appear. You can also create a new menu by entering its title (up to 10 characters) in the text entry box. New menus will be added to the right of existing menus in the menu bar. The name of the macro (up to 20 characters) should be entered in the

text entry box.

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Enter the name of the new macro

Choose the menu to which the new macro will be added

Assign a keyboard shortcut

Create a new menu, if desired

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An optional keyboard shortcut can be assigned to the macro as well: type a single lower-case letter or number in the text entry box. An alert box will warn you if you choose a character already in use, page 129, but you can override the previous assignment.

The Size indicator tells you the number of steps recorded, and the memory used by the macro. Click the button to discard the macro you have just recorded. Clicking the button closes the dialog box and you can continue to record more steps in the macro. Click the button to add the macro to the bottom of the selected menu.

Until you save the file, new macros exist only in memory and are not permanently stored. If you open another file (without discarding currently available macros) and save that file, the macros will become part of the new file. When you quit Scope, you will not be asked to save changes if the changes are only concerned with macros, so it is a good idea to save the file each time you create a macro (or save the file’s macros as various macro files).

Replaying a Macro

Once assigned a name and location, a macro acts like a menu command: select it from its menu or type its keyboard shortcut. While a macro is being replayed, the message is displayed in the e-corder panel (but not the Stim panel), and no other functions can be performed within Scope. If you switch to other software, leaving Scope in the background, the macro stops playing at its current step. To manually stop a macro type Ctrl+period ( -period on Macintosh)).

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Deleting a Macro

To delete existing macros, choose the Delete Macro menu command in the Macro menu, Figure A–9, page 127, which accesses the Delete Macro dialog box, Figure 7–11. To delete a macro, select its name and click the button. To choose multiple macros for deletion, Shift+click or Shift+drag to select adjacent macros, or Ctrl+click ( –click on Macintosh) to select or deselect macros individually. If you double-click a macro name it will be deleted and close the dialog box.


Figure 7–11 The Delete Macro dialog box

When a file is saved, all currently available macros are saved with it. When you delete a macro, you delete it from memory. If the macro is part of the current file, it is deleted when the file is saved — if you quit or close the file without saving changes the file can be reopened with the macro intact.

Options When Recording Macros

Operations involving files and dialog boxes can be made to behave differently when playing macros, depending on whether you want to do the same thing all the time, allow user modification, and so on.

Changing Dialog Box Settings

Macros can be used to change dialog box settings and parameter values, or to open a dialog box for so that you can change settings as

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the macro is played.

To use a macro to alter settings in a dialog box, select the dialog box while macro recording is in progress Change the dialog box settings, and then click the OK button. The new values of your changes are recorded — if you do not alter a setting then it is recorded as ‘no change’ and when the macro is replayed the current value of that setting will be used. If you click Cancel, the changes made in the dialog box will be ignored. When replaying the macro, the settings are changed without displaying the dialog box.

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Figure 7–12 The Macro Open directory dialog box

To create a macro step that will allow you to change dialog box settings when replaying the macro, hold down the Alt key (Option key on Macintosh) when selecting the command that shows the dialog box, then click the OK button. Do not make any other changes in the dialog box. When the macro is replayed, the dialog box will be opened so that you can change the settings; click the dialog box OK or Cancel buttons so that the macro replay can continue, with any new settings that you have made.

Starting Sampling

Macros can be used to control when sampling starts and stops: click the Scope Start button at the appropriate step while recording a macro. Repetitive or superimposed sampling will give only a single sweep in this case, otherwise the macro would never end.

Opening Files

A macro can be used to open the same file each time it is played, or to allow the user to choose a file to open. To open a particular file, choose Open… from the File menu while the macro is being recorded: the Macro Open directory dialog box is displayed, Figure 7–12.

To choose which file is to be opened when the macro is replayed, press the Alt key when selecting the Open… command while recording a macro. An alert box reminds you that you are giving the user a choice. The Open directory dialog box, Figure 2–2, page 11, will be displayed when the macro is played.

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Figure 7–13 The Macro Save As directory dialog box

If the chosen file has been moved (or deleted) since the macro was recorded, then Scope searches in the most recently used folder and in the same folder as Scope. If the file is in neither of these locations, an alert box warns you that Scope cannot find the file, and the Open directory dialog box is displayed to locate the file — if you click the Cancel button, the macro will stop.

Saving Files

When playing a macro, you can save data in a single or a series of files. Use the normal Save command in a macro to save a current named file. You might want to do this at specified intervals to ensure the collected data is backed up in the event of a power outage. Press the Alt key (Option key on Macintosh) when selecting the Save command to decide the location and name of the file when the macro is replayed — the Save As directory dialog box, Figure 5–6, page 68, will be displayed when the macro is replayed.

While a macro is being recorded, the Save As… command accesses the Macro Save As directory dialog box, Figure 7–12 which can be used to save a data file with a unique file name during macro replay.

Three checkboxes allow you to specify the unique file names:

• Unique number, a different number is added to the end of the file name each time the file is saved during macro replay. Numbers are added in sequence, for example, if the file name is CoolData, then

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files will be saved as CoolData(001), CoolData(002), etc. If the macro is stopped (or finished) and replayed again, numbering will recommence from the last such numbered file, to give CoolData(003) etc.;

• Time, appends the current time to the file name. This checkbox is disabled if the Unique number checkbox is ticked.

• Date, appends the current date to the file name. This checkbox is disabled if the Unique number checkbox is ticked.

If no checkboxes are ticked, then each time you replay the macro, the file will be overwritten.

Macros Using Macros

New macros can use existing macros as part of their command sequence but macros can only be nested up to ten deep. An alert box will appear during the of your macro replay if the combination becomes too recursive. If a macro is called by other macros, Scope warns you if you attempt to delete it. If a macro being replayed calls a deleted macro, an alert box will appear, and the replay will halt.

Complex macros are often best constructed by creating a series of short macros then a master macro that calls the other macros in sequence.

Macro Commands

Special macro menu commands are available from the Macro Commands submenu, Figure A–10, page 128, while recording a

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macro. These are discussed in the following sections.

Update Screen

By default he Update Screen menu command is ticked and when a macro is played, the screen is updated after each macro step. Clicking Update Screen command to untick it causes the macro to play without updating the screen. Update Screen can be toggled off or on at any stage of a macro. In either case the screen will be redrawn when the macro is finished.

Macro replay can be faster if Update Screen is off.


Figure 7–14 The Macro Wait dialog box, with the three options selected

Figure 7–15 The Macro Wait dialog box during the playing of the Wait step of a macro

Wait…

The Wait… macro command, Figure A–10, page 128, accesses the Wait dialog box, Figure 7–14. A pop-up menu lets you select:

• Wait For a set length of time (for example, 55 seconds);

• Wait Until a certain time (for example, 11:20 a.m.); or

• Wait Until the Next time division (for example, at the next hour);

before the macro continues.

The checkbox lets you choose whether the dialog box, shown in Figure 7–15, appears during the wait period of the macro replay. As well as giving a visual indication of wait progress, you can also proceed immediately to the next step of the

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NotePreceding an alert box with an audible signal

Figure 7–16 The Browse for Sound File directory dialog box

macro (click the button), or abort the macro (click the button). You can also type Ctrl+period (or -period on

Macintosh) to abort the macro.

Play Sound…

On Windows computers the Play Sound… macro command, Figure A–10, page 128, accesses the Browse for Sound File directory dialog box, Figure 7–16, to set and audible alerts during macro replay. On Macintosh, the Macro Play sound dialog box is opened, and you can select from the range of sounds in your computer’s system.

Click the name of a sound in the list to select it. If you want to hear the selected sound, click the Preview button. To have it actually played in the macro, click the Open button. To save time in creating multiple sounds, you can create a library of sound macros, and simply incorporate one or more of them in the macro that needs them.

You might wish to have three beeps signal when the e-corder starts recording data, or a bell and a whistle when a trigger point has been reached. You can even record short verbal cues using the Sound

(using the Play Sound… command) is useful to draw attention to the screen

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Windows computers

Macintosh computers


Figure 7–17 The Macro Message dialog box

Recorder accessory (if your computer has a microphone input) and use these in your macros.

If a macro attempts to play a sound not in the computer system (since removed from the system), then another sound will be substituted.

Message…

The Message… macro command accesses the Macro Message dialog box, Figure 7–17. This lets you display alert boxes requiring user response at certain stages during macro replay. You can type in the a message of up to 255 characters. The dialog box produced will have an OK button (which will close the box and continue with the macro replay) and, if the checkbox is ticked, a ‘Cancel’ button for exiting the macro.

Choose an icon to be displayed with the message during macro replay

Include a Cancel button with the macro message to abort macro replay

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Speak Message… (Macintosh only)

If you choose the Speak Message… macro command, the Speak Message dialog box appears, Figure 7–18. You can type in the message of your choice (up to 255 characters) which will be spoken by the computer during macro replay. Speech is generated phonetically so, for example, if you were to enter Chinese words as phonetic English then Chinese words would be spoken.

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Figure 7–18 The Speak Message dialog box (Macintosh only)

The volume at which the message is spoken can be set to Default (the volume set in the Macintosh Sound control panel), or from 1 to 7, which overrides the system setting.

Three radio buttons give a choice of actions when the macro step is replayed:

• Never Show, the message will be spoken if speech is enabled, otherwise a standard system beep is used;

• Show if Speech not Available, the message is spoken if speech is enabled, otherwise an alert appears displaying the written message and the macro is paused until alert box OK button is clicked;

• Always Show, an alert box always appears, displaying the written message, whether or not a spoken message occurs. The macro is paused until the alert box OK button is clicked.

AppleScript… (Macintosh only)

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This macro command allows you to insert an AppleScript as a macro step. AppleScript is a scripting language for automating tasks, and controlling applications and their interactions through Apple events. To use it, you must have AppleScript installed on your computer. On selecting the AppleScript… macro command, the AppleScript from Macro dialog box appears, Figure 7–19.

You can enter a script of 32 000 characters in the scrolling field. The dialog box is a movable modal one, which means you can switch out of Scope, to get tested scripts from the Script Editor, say, and paste them in, but you will lose text styles from a formatted script if you do


Figure 7–19 The AppleScript dialog box (Macintosh only)

Table 7–1 AppleScript commands

this. Scripts are just left as unformatted text in the dialog box, even when compiled there.

Click the button to check and compile the script — you are will be warned if the script will not run. The AppleScript is also checked and compiled once you click the button. Note that an application must be called by its name exactly as it appears in the Finder (for example ‘Scope v3.6’, not just ‘Scope’).

Once you click the button, the AppleScript is stored as one step of the macro and then cannot be re-edited. Complex scripts that might require re-editing are better left residing in the Finder, and then called using a simple AppleScript macro step within Scope.

Scope is Apple event aware, but not Apple event recordable, and has no dictionary. It supports the open, print, quit, run and do script commands, Table 7–1.

The macro to be played by the do script Apple event is identified by the

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name of the menu that the macro is in, a colon, and the name of the macro (as it is shown in the Delete Macro dialog box, Figure 7–11, page 113). Scope is automatically brought to the front when a do script event occurs.

Command Function Example

open Open a specified Scope document open file "Test Results"

print Print a specified Scope document print file "Test Results"

quit Quit Scope application quit application "Scope"

run Launch Scope application run application "Scope"

do script Play the specified Scope macro do script "Macro:Beep"

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Figure 7–20 The Begin Repeat dialog box

If an AppleScript macro step both switches out of Scope to some other program and then switches back in, the macro continues and completes any remaining steps. If the AppleScript switches out of Scope, but does not switch in again, then the macro finishes at that step, and any remaining steps are ignored.

As an example of its use, the menu commands in a new Tutorial menu (created using macros) might use AppleScript to take students to particular cards in an especially written HyperCard stack that teaches them about Scope or guides them through an experiment. HyperCard can then use a script to return to Scope, set things up, and so on.

Additionally, you could transfer data to an Apple event aware spreadsheet as you worked through a Scope file, by running a macro to cut a line from the Data Pad, and using an AppleScript step to switch to the spreadsheet, paste the data into the next row, and switch back to Scope again.

Begin Repeat

The Begin Repeat macro command is used to enter a number, Figure 7–20, to repeat groups of steps in a macro. You may repeat any group of commands up to 100 000 times. This could be used, for example, to set up fast sampling at staggered intervals overnight. For each Begin Repeat you should specify an End Repeat, page 123. If you do not specify enough End Repeats, they are automatically added when you select Stop Recording…

Repeat for Each Page

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Use this macro command to perform some operation on each overlaid page of data, indicated as shown in Figure 7–21. The Average page, blank page, and pages not in the overlay are ignored. See Overlaying Pages, page 55, for information on how to set an overlay.


Figure 7–21 Repeat for Each Page macro: the affected pages are those selected for overlay.

When this macro command plays, it will go through the Scope file and display each page it operates upon, unless the Update Screen command is turned off. You should specify an End Repeat after the instructions you want performed with the Repeat for Each Page.

End Repeat

Each Begin Repeat, or Repeat for Each Page, macro step should be paired with an End Repeat. If you do not specify enough End Repeat steps, they are automatically added when you choose Stop Recording….

Analysis ScopeRename the Scope software on the computer hard disk (not the desktop shortcut) by prefixing it with the word ‘Analysis’, for example Analysis Scope, or Analysis Scope.exe. Scope will then always open in analysis mode, bypassing hardware initialization. This is useful if you are using Scope on a second computer, without an e-corder attached, to review and analyze existing data files — the Hardware Not Found dialog box will not appear, Figure 1–2, page 4

Only these are included in the overlay

Average page Blank (last) page

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This is equivalent to setting Scope to always open in analysis mode in the Hardware Start Up Options dialog box, page 109.

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A–1 ontrol menu ows computers

A P P E N D I X A

Menus & Commands

MenusThe menus shown here are the default settings, and your copy of Scope may be set up differently, since Scope menus can be extensively customized. Scope has seven menus: File, Edit, Setup, Display, Windows, Macro and Help; more can be added with macros. Some of
the menu commands shown will change or be disabled depending on the active window and what, if anything, is selected. An ellipsis (…) after a menu command indicates that it accesses a dialog box; any keyboard shortcut, page 129, is also shown after the menu command; and an adjacent tick indicates that the command is currently active.
125

The following figures show menus as they appear on a Windows computer. Corresponding menus on Macintosh are similar except that keyboard shortcuts shown as using the Ctrl key use the key on Macintosh.

Restore window to previous size from maximised stateMake window moveable with keyboard arrow keysMake window resizeable with keyboard arrow keysShrink active window (all of Scope) to button on taskbarExpand active window to take up nearly all the screen

Close the application window and exit (quit) Scope

Create a new Scope fileOpen an existing fileCreate a new Scope fileOpen an existing file

Figure A–2 The File menu

Undo previous action (if possible)

Cut selected data to the ClipboardCopy selected data to the ClipboardPaste selection

Close the current fileSave the current fileSave file with a new name, or format

Set up page size and so on to suit the printerPrint one or more pages of data

Exit Scope (Quit on Macintosh)

Close the current fileSave the current fileSave file with a new name, or format

Set up page size and so on to suit the printerPrint one or more pages of data

Exit Scope (Quit on Macintosh)

Figure A–3 The Edit menu

Clear selection

Copy text or graphics to the Clipboard

Customise Scope options (see submenu)

126 Scope Software

Figure A–4 The Preferences submenu

Figure A–5 The Setup menu

Look for hardwareSet external trigger typeChoose default settingsModify Scope menusModify Scope panel behavioursSave current settings as defaults

Configure sampling parameters (sweep and trigger controls)

Configure the output waveform (pulses, ramps, etc.)Set the constant output voltage

Figure A–7 The Display menu

Modify display colors, grids, lines, etc.Label the Time and Amplitude axesGo straight to a particular page of a file

Show or hide an overlaid pageTurn all overlays onTurn all overlays offModify appearance of overlaid waveforms

Hardware, software, and contact informationFigure A–6 The Help menu, Windows computers. Use the Apple menu on a Macintosh.

Subtract the background from all pagesSet current page as the background Turn off the background waveform

Overlay the stimulation waveform on the data

Apply various computations to the raw data

Open Notebook window

Return to or open the Scope window

Figure A–8 The Windows menu

Appendix A — Menus & Commands 127

Figure A–9 The Macro menu

Display a selection in the Zoom window

Display and adjust settings for selected areaDisplay and adjust Marker settings

Open the Data Pad windowMake new entry in the Data Pad

Start or stop recording a macroDelete a macro

Open submenu shown in Figure A–10

128

Figure A–10 The Macro Commands submenu

Table A–1 Keyboard shortcuts

Windows Macintosh Function

Ctrl+A –A Overlay all

Ctrl+B –B Clear selection

Ctrl+C –C Copy to Clipboard

Ctrl+D –D Add information on selection to Data Pad

Ctrl+F –F Set up computed functions

Ctrl+G –G Go to a page

Ctrl+H –H Overlay none

Ctrl+N –N New

Ctrl+O –O Open

Alt+F4 –Q Quit

Ctrl+P –P Print

Ctrl+R –R Start/stop macro recording

Redraw the screen during macro replay

Pause the macro for a set time

Set an audible alert using the system sounds

Display a message dialog box

Speak a message (Macintosh only)

Add an AppleScript (Macintosh only)

Select each page of data to manipulateStart a repeat sequenceFinish a repeat sequence

Scope Software

Ctrl+S –S Save file

Ctrl+V –V Paste

Ctrl+W –W Close active window

Ctrl+X –X Cut selection

Ctrl+Z –Z Undo/redo (if possible)

Ctrl+\ –\ Access to dialog boxes (Menu, Save As, Start-up)

Ctrl+Period (.) –Period (.) Stop sampling, stop macro recording or playing

Ctrl+Spacebar –Spacebar Start/stop sampling (this shortcut may not work on some computers)

Ctrl+Right arrow –Right arrow Go to end of file

Ctrl+Left arrow –Left arrow Go to start of file

Appendix A — Menus & C

Keyboard ShortcutsFactory default Keyboard shortcuts are shown in Table A–1. Shortcuts can be reassigned with the menu editor, page 106, or with macros page 111. The commands are context sensitive and may change or be disabled depending on the active window and whether a selection of data has been made.

Standard keyboard shortcuts for dialog boxes also apply:

• Tab moves the insertion point to next text entry box;

• Enter or Return is the same as clicking the OK button; and

• Ctrl+. ( -. on Macintosh), or Esc, is the same as clicking the Cancel button.

On Windows computers only, you can press the Alt key to activate menus, use left and right arrow keys to select a menu, and the down arrow key to show it (or press the Alt key and then type the underlined letter in the menu title to show it). Menu commands have underlined letters: type the letter to choose the command in an active menu. Use the up and down arrow keys to select and highlight a menu command, and then press the Enter key to choose (activate) it.

ommands 129

130
Scope Software

Scope

FigureThe Abox.

Software

B

A–1 bout Scope dialog

A P P E N D I X B

Troubleshooting

Technical SupportIf you are experiencing difficulties with Scope that are not covered in this manual, or you need technical assistance with your e-corder system, then eDAQ and its authorized distributors are glad to help. Use the About Scope… command from the Help menu (Apple menu on Macintosh) to access the About Scope dialog box, Figure A–1, which provides contact and system information.

Dealer and Distributor Information

Click the Telephone button, , to display a list of eDAQ offices, Figure A–2. You can also visit the eDAQ web site to obtain the latest information.

131

version and release date

Click for System Information, Figure A–3

Click for Contact Information, Figure A–2

Click anywhere on the main part of the box to cancel it

http://www.eDAQ.com

http://www.eDAQ.com

http://www.eDAQ.com

132

The eDAQ Addresses dialog box

Figure A–3 The Information dialog box

System Configuration Information

Click to copy the information for pasting into an email, or fax document

Internet links

Click to copy the text to an email or fax

Figure A–2

Scope Software

Click the Computer button, , to access the Information dialog box, Figure A–3 which gives information on which version of Scope is running, together with the system software. Also provided is a detailed description of your computer, your e-corder and how it is connected, connected eDAQ Amps (if any), and other peripheral devices connected to the computer.

Use the Print… button or Copy All button to send the information via fax or email to your eDAQ distributor if required.

Appendix A — Troubleshoo

Solutions to Common ProblemsScope has an extensive array of dialog and alert boxes, and these will probably appear in most cases where problems arise. Very often they will suggest appropriate courses of action. Where they do not, or where the actions they suggest fail to alleviate the problem, this section of the guide should prove useful.

Your e-corder Manual will also have suggestions.

The computer can’t find the e-corder on start-up

• Check that the e-corder is on, and plugged into a working power socket.

• Ensure that the USB cable is firmly attached at both ends. Try a new cable if possible.

• Turn everything off for at least 10 seconds. Turn the e-corder and computer back on. Turn on the computer and try using the software again.

Scope ‘hangs’ or gives an alert on start-up

• It may be that the copy of the Scope software has become damaged in some way. Try reinstalling Scope from the original CD.

Scope starts up with strange settings and/or macros

• Opening a data file with custom settings or a settings file, will start

ting 133

with the settings of the file. Start up again using the Scope software icon or its desktop shortcut.

• Start-up settings may have been customized. To start up Scope with its factory default settings, hold down the Ctrl key ( key on Macintosh) as you open Scope.

• To remove customized start-up settings, choose the Start-Up… submenu command from the Preferences submenu of the Edit menu and click Clear in the dialog box that appears.

134

Keyboard shortcuts don’t work, or do strange things

• If your menu commands are missing, or keyboard shortcuts reassigned, they may have been customized. Compare menu commands and keyboard shortcuts to those shown in Appendix A.

• Start-up settings may have been customized. To start up Scope with its factory default settings, hold down the Ctrl key ( key on Macintosh) as you open Scope.

• To remove customized start-up settings, choose the Start-Up… submenu command from the Preferences submenu of the Edit menu and click Clear in the dialog box that appears.

• Type Ctrl+\ ( -\ on Macintosh) for emergency access to the menu settings, start-up settings, and saving options.

Alert boxes say the sampling rate is too fast

• Scope can sample only on one channel at 200 kHz, page 24, ensure the second channel is turned off.

• External and Line options set in the Sampling dialog box will not work at a sampling rate of 200 kHz.

Nothing seems to be recording

• Scope may be sampling, but when data is acquired at a fast speed (400 Hz or more) it may be displayed once the sweep is over. The e-corder does computed functions and digital filtering itself, and this may also increase the delay between sweeps. If Scope is sampling, then there will be an indication in the e-corder

Scope Software

(or Stim) panel.

• Apply complex transformations (such as FFTs) after recording.

• The Trigger may not be set to User, and Scope may be waiting for a trigger event: the word ‘Sampling…’ will show in the e-corder panel. The e-corder will also indicate it is waiting for a trigger (see the owner’s guide for your e-corder).

• The Stimulator is in use (the Stim panel is showing), the Stimulator External Trigger is on, and Scope is waiting for the event. The Start/Stop button will read Stop. The e-corder also indicates it is waiting for a trigger.

Appendix A — Troubleshoo

The computer ‘hangs’ while recording, or there is data loss

• Ensure that the USB cable is firmly attached at both ends and try again. If there is still a problem, try a new cable.

• Check your network connections, if you are on a network.

Only one page printed, although a page range was specified

• Scope has a specific option in the Print Options dialog box, the Print Current Page Only checkbox, which is on by default. When the checkbox is on, the active page prints regardless of the range, if any, specified in the Print dialog box. Click the Options… button in the Print dialog box to display the Print Options dialog box.

• To print a range of pages, turn off the Print Current Page Only checkbox, and enter the numbers as usual.

Scope quits unexpectedly, crashes, or freezes

• The file you are using may have become corrupted. Use disk-checking software to find and fix the problem.

• It may be that the copy Scope software has become damaged in some way. Try reinstalling Scope from the original CD.

• It could be that a computer virus is causing the problems. Check your disk with anti-viral software.

• If the problem occurs again please contact eDAQ.

ting 135

136
Scope Software

Scope
Software
C
A P P E N D I X C
Technical Notes

Fast Fourier TransformsScope uses a discrete FFT (Fast Fourier Transform) algorithm to convert data from time to frequency domains, page 93. For a detailed discussion of the FFT see Numerical Recipes: The Art of Scientific Computing, W.H. Press et al., Cambridge University Press, 1986.

The FFT algorithm requires 2n data points where n is an integer. Scope pages contain 256, 512, 640, 1024, 1280, or 2560 data points. Pages with 256, 512, or 1024 samples can be transformed directly. Pages with 640 or 1280 points first require ‘zero padding’. That is, the signal is lengthened before FFT calculation to 1024 and 2048 points respectively by adding points with a value of zero equally at the start and end of the sweep. Pages with 2560 samples have the FFT calculated from the first 2048 data points, the last 512 points are ignored and do not contribute to the FFT.

137

Consider a sequence of N consecutive data points, at a time interval ∆, described by a function hk ≡ h(tk) where tk ≡ k∆ is the time value of sample k, where k is the series 0, 1, 2, … N–1. The FFT transforms these N discrete samples in time, with h voltage (or derived units), to N discrete samples in frequency, with H frequency amplitude. The frequencies can be assigned the discrete values fn = n/N∆, where n is the series –N/2, …, (N/2)–1. The discrete FFFT is defined by:

Hn hke2πikn N⁄

k 0=

N 1–

∑≡

138

This transform maps N complex numbers hk into N complex numbers Hn. For signals that Scope measures, numbers hk are real with the imaginary part set to zero. Zero frequency corresponds to n = 0; positive frequencies correspond to values 1 ≤ n ≤ ((N/2)–1). The function can be seen to be periodic in n with period N, with H–n = HN–n for values of n other than zero. One can let the n in Hn range from 0 to N–1 so that the correspondence between k in the time domain and n in the frequency domain is more obvious (but we don’t for this treatment).

If we take Re and Im to be respectively the real and imaginary parts of the nth frequency component, then the amplitude of the nth frequency component of the spectrum may be expressed as:

The vertical, intensity, axis of the FFT can have a linear (units derived from the signal units) or logarithmic scale (units of deciBels, dB). The logarithmic display shows the relative attenuation of spectral lines with respect to the largest spectral line (set to zero decibels). It compresses the data into logarithmic decades, making discernible smaller components that might otherwise be difficult to see on the display because of a large dynamic data range. It derives from the formula dB = 20log(A1/A2).

Terminology

The power spectrum Scope derives using the FFT is, technically, the

A n( )Re Hn( )( )2 Im Hn( )( )2+

N 2⁄--------------------------------------------------------------=

Scope Software

modulus of the amplitude spectrum. The terms amplitude spectrum and power spectrum are sometimes used loosely. However, strictly speaking, an amplitude spectrum can have negative values (indicating phase), while a power spectrum uses the square of the signal amplitude. If you compare power spectra obtained with Scope with those of other software, it is important that you establish that comparing to other power spectra.

FFT Windowing Functions

The FFT algorithm assumes that data points of a sweep represent an integral number of cycles of a periodic waveform. However, as is

Appendix C — Technical N

Figure A–1 FFT Windowing functions

likely, the first and last values of the signal in a sweep do not join smoothly together, then a spurious frequency reading will be detected at the edge of the sampling window by the FFT: this is known as an ‘edge effect’. The accuracy with which an FFT can resolve frequencies depends on the sampling rate, 1/∆, and the number of points sampled, N. If a frequency reading is not an integral multiple of 1/∆N Hz, then it will be resolved into peaks above and below that value, distorting the result. Setting N at a large value (1024 data points, or more, for sweeps that are to be used for FFT) minimizes these problems.

Cosine Bell window

Hamming window

Blackman window

wn 0.42 0.50 2πnN

---------- cos+= 0.08 4πn

N---------- cos+

wn 0.50 1 2πnN

---------- cos+=

wn 0.54 0.46 2πnN

---------- cos+=

For all equations n is a value between –N/2 to (N/2)–1, and N is the number of sampled points. The equations can be defined over positive values of n from 0 to N–1 simply by rearranging them

otes 139

Windowing functions reduce the importance of data at the edges of the window of data used by the FFT, preventing spurious peaks arising from edge and related effects. The discrete Fourier transform data are multiplied by the windowing function wn to weight them:

Three of the more common windowing functions (cosine Bell, Hamming, and Blackman) have been provided in Scope, Figure 6–14, page 94, and their details are described in Figure A–1.

Hn wnhke2πikn N⁄

k 0=

N 1–

∑≡

140

Computed FunctionsThe information in this section describes the mathematics involved in some of the computed functions available in Scope.

Smoothing

Signals can be smoothed as described on page 97. A number (1 – 50) is entered to indicate degree of smoothing, n, but at the start and end of the sweep it is not possible to use the full degree of smoothing. If N is the number of points in the sweep, and the original signal is described by f(i) at point i, where 0 ≤ i ≤ N–1, then each point on the smoothed signal, g(i), can be expressed by the equation:

Integral

Integration can be done using one of the Data Pad Integral functions, page 89, or by using the Integrate computed function, page 99, but in

g i( )

1n i 1+ +--------------------- f j( )

j 0=

i n+

∑

12n 1+----------------- f j( )

j i n–=

i n+

∑

1N 1–( ) i n–( )– 1+

--------------------------------------------------- f j( )

j i n–=

N 1–

∑

=

0 i n 1–≤ ≤[ ]

n i N n– 1–≤ ≤[ ]

N n– i N 1–≤ ≤[ ]

Scope Software

either case a similar calculation is done. Sloping baselines set with the Markers, page 83, are ignored for the purposes of integration. Background subtraction, page 86, is done from the integrated wave.

If ∆t is the time between consecutive data points, and the original signal amplitude is f(j), then for each position i in the integrated signal, g(i):

g i( ) ∆t f j( )

j 1=

i

∑=

Appendix C — Technical N

Figure A–2 Determination of signal derivative (slope)

That is, the integral at the ith point in a signal is the sum total of the amplitude of the data points, up to and including the ith point, multiplied by ∆t. Data Pad Integral functions use only data points from the start time to the end time of the selected portion of the signal. Integral Abs, Integral Positive, and Integral Negative Data Pad functions sum the absolute, positive or negative signal amplitudes respectively.

Differential

The differential of a signal is obtained using the Differentiate computed function, page 99. In a sweep of N points, the value of the differential at a point i, where 0 ≤ i ≤ N–1, is the average of the slope of two lines, one joining point i–1 to i, and the other between point i and i+1, Figure A–1.

Note that at the start and end of the sweep it is not possible to do this and that the first differential values is defined by the slope of the line between the first two points, while the last differential value in a sweep is defined by the slope of a line joining the last two points.

Thus for a sweep of N data points, at a time interval of ∆t, where the data points have an amplitude of f(j), the differentiated value, g(i) is determined by the equation:

g i( )

f 2( ) f 1( )–∆t

---------------------------

f i 1+( ) f i 1–( )–2∆t

------------------------------------------

=

i 0=

1 i N 2–≤ ≤[ ]

otes 141

f N 1–( ) f N 2–( )–∆t

-------------------------------------------------

i N 1–=[ ]

i

i+ 1i– 1

Slope at point i

∆t True signal

142

Slope

The Data Pad Slope function, page 90, has three options:

• Average Slope, is calculated for an active point (where the data display area was last clicked) as described in page 139. However if a selection of region of the signal has been made then the least squares line of best fit is determined for the selection, and the slope of this line is reported.

• Maximum Slope, the slope for each point is calculated as in Figure A–1 and the maximum slope value for points in the selection is reported.

• Minimum Slope, the slope for each point is calculated as in Figure A–1 and the minimum slope value for points in the selection is reported.

Scope Software

Scope

AppleAppleAppleAppleautomAveraAvera

paveraaxis laAxis laAxis L

Index

AAbout Scope dialog box 131About Scope… command 131Abs 98absolute value 98access to Chart 3Add 98Add Macro to Menu dialog box 111Add to Data Pad command 88adding data to the Data Pad 88Amplitude axis 15, 48–49, 58analysis 9, 81–99analysis mode 10, 123Analysis Scope 123appending data files 70

BBackground buttons 51background page 86background recording 17background subtraction 86, 140baseline 83–84

and integration 140non-linear 86

Begin Repeat command 122Begin Repeat dialog box 122bipolar display 48Browse for Sound File directory dialog box 118

Ccalibrating a signal

Units Conversion 29

Software 143

Script 120–122Script commands 121Script dialog box 121Script… command 120ating Scope 110–123ge control 34ge page 91–92rinting 75, 92ged sweeps 34bels 49–50bels dialog box 50

abels… command 49

calibration 31caret symbol, ^ 50Cell button 87channel controls 15, 24Channel pop-up menu 24channel separator 16, 46Clear Background command 86Clear command 64Clipboard 67Clipboard Viewer 67close button 13

Close command 12closing a Scope file 12Color pop-up menu 51, 54color printing 75comments 78computed function

Abs 98Add 98Differentiate 99, 141Divide 98Integrate 99, 140Invert 98Multiply 98Reciprocal 99Shift 97Smooth 97, 140Square 99Subtract 98

computed functions 95–99, 140–142channel display 47, 96sampling speed 96units 96

Computed Functions dialog box 47, 95Computed Functions… command 47, 96computer requirements

Windows computer 2constant output voltage 42control handle 39Control Options dialog box 107control panel

Cursor 16Input A 15, 24

Copy Special… command 65Copy Zoom window to Clipboard dialog box 66copying data

as picture 65as text 66from Data Pad 66

Cursor panel 16customized stimulus waveforms 40customizing Scope 10, 101Cut command 64

Ddata display area 16, 46data file 67data loss 103, 135Data Pad 65, 69, 87–91

adding data 58, 88functions 89–90limits 87printing 77, 91saving as text file 69setting up 89–90

Data Pad Column Setup dialog box 89Data Pad command 87Data Pad Value miniwindow 90Data Pad window 87data resolution 24dealer and distributor information 131default settings 10, 108Define Unit Name dialog box 32

144 Scope Software

Input B 15, 24Stim 42Time Base 15, 22, 104

control panels 14hiding 106–107moving 107position 106

controls and display 8Controls… command 106Copy command 64Copy Data Pad to Clipboard dialog box 66Copy Scope Window to Clipboard dialog box 66

defining unit names 32defining units 32degree sign, ° 49delay between sweeps 35Delay control 35Delete Macro command 112Delete Macro dialog box 113Delete Unit Name dialog box 33deleting unit name 33deleting units 32delta symbol, ∆ 49

differentialslope 141

Differentiate 99, 141Display menu 127

Axis Labels… command 49Clear Background command 86Computed Functions… command 96Display Settings… command 50, 52Go To Page… command 14, 55Overlay All command 55Overlay Display Settings… command 52Overlay None command 55Overlay Stimulator… command 53Set Background command 86Show Overlay command 55Subtract Background command 86

display offset 28Display pop-up menu 92, 93, 96

hiding 103display settings 50–54Display Settings (FFT) dialog box 52, 93Display Settings (X–Y) dialog box 52, 92Display Settings dialog box 50Display Settings… command 50, 52Divide 98divisions 22Double stimulus waveform 38duplicate Marker 83

Eearlier versions 3

exiting Scope 5, 12

FFFT display 93–95, 137–139

edge effect 139reference level 95settings 52, 53terminology 138windowing functions 94, 138–139

FFT Options dialog box 94File menu 126

Close command 12Exit command 12New command 11Open… command 11, 70Page Setup… command 73Print… command 75Quit command 12Save As… command 65, 67–69Save command 67

file typesdata 67macro 69settings 68text 68–69

filtering 27AC coupling 27low-pass 27

Free Form stimulus waveform 38, 40–41Function pop-up menu 99

G

Index 145

eDAQ Addresses dialog box 132Edit menu 126

Clear command 64Copy command 64Copy Special… command 65Cut command 64Paste command 64Save As… command 115Undo command 64, 65

emergency access 108–109End Repeat command 123Eraser tool 41Exit command 12

Go To Page dialog box 55Go To Page… command 14, 55graticule 22Graticule buttons 51

HHelp menu 127

About Scope… command 131high-resolution printing 74

IInformation dialog box 132Input A panel 15, 24input amplifier 26–28Input Amplifier dialog box 25Input Amplifier… button 15Input B panel 15, 24Input Voltage dialog box 28installing software 3–5Integrate 99, 140Invert 98

Kkeeping partial data 103keyboard shortcuts 14, 54, 106, 128

changing 106macros 112

LLine tool 41Load Text File dialog box 72logarithmic display 95

MMacintosh to Windows 11macro commands 116–123Macro Commands submenu 128

AppleScript… command 120

Macro Open directory dialog box 114Macro Save As directory dialog box 115Macro Wait dialog box 117macros 110–123

called by other macros 116changing dialog box settings 113–114commands 116–123deleting 112–113keeping records 110keyboard shortcuts 112loading 110master macro 116nesting 116opening files 114recording 111–112replaying 112sampling 114saving 111–112saving files 115–116stopping 112versions 110

Marker 16, 58, 82–86independent 82locked to waveform 82

Marker command 84Marker miniwindow 84–85Math pop-up menu 98measurement

relative 82–83menu commands

hiding 105locking 106

menus 125–128

146 Scope Software

Begin Repeat command 122End Repeat command 123Message… command 119Play Sound… command 118Repeat for Each Page command 122Speak Message… command 119Update Screen command 116Wait… command 117

macro file 69Macro menu 127

Delete Macro command 112Start Recording command 111

Macro Message dialog box 119

altering 105–106hiding 105

Menus dialog box 105Menus… command 105Message… command 119micro symbol, µ 49Mode pop-up menu 33, 37moving control panels 107Multiple stimulus waveform 38multiple sweeps 34Multiply 98

Nnavigating 14, 54New command 11New Hardware wizard 3new menus 111non-linear baseline 86Notebook 78–79

printing 79Notebook command 78Notebook window 79number of pulses 40

Oold versions 3omega synbol, Ω 49Open directory dialog box 11, 70Open… command 11, 70opening a Scope file 10Options… command 102Output Voltage… command 42Overlay All command 55Overlay Display Settings (FFT) dialog box 53Overlay Display Settings (X–Y) dialog box 53Overlay Display Settings dialog box 52Overlay Display Settings… command 52Overlay None command 55Overlay Stimulator dialog box 54Overlay Stimulator… command 53

number of data points 72Page button 86Page button pop-up menu 56Page buttons 14, 54, 55–56Page Comment button 16, 78page comments 78

editing 78printing 77, 78

Page Corner controls 14, 54Page Layout dialog box 77page setup 73–75Page Setup dialog box 73Page Setup Options dialog box 74Page Setup… command 73Paste command 64pasting text into Scope 72Pencil tool 41Play Sound… command 118pointer 17

cross 82dragging 49heavy cross 87I-beam 88resizing 88stretching 49

PowerLab Settings 32PowerLab Unavailable dialog box 4preferences 102–106preferences file 32, 108Preferences submenu 126

Index 147

overlayingchannels 46–47display settings 52pages 55–56stimulus waveform 53

overview of Scope 8–10overwriting data 103

Ppage

and FFTs 137definition 14, 54

Controls… command 106Menus… command 105Options… command 102Start-Up… command 107

Print Current Page Only checkbox 75, 135Print dialog box 76Print Options dialog box 76Print… command 75printing 73–77

Average page 75, 92color 75commands 75Data Pad 91

high-resolution 74Notebook 79page comments 77, 78Scope pages per sheet 73–74Scope window 76Zoom window 59

Progress Indicator display 18Pulse stimulus waveform 38

QQuit command 12

RRamp stimulus waveform 38range 24, 26Range pop-up menu 15, 24, 39Read Text Options dialog box 71Reciprocal 99recording 8, 17–19

changing settings during 19display during 18interruptions during 19, 103length 19on blank page 103

recording fidelity 13, 24, 46recording length 19reference level 95re-order pages 64Repeat for Each Page command 122repetitive sweeps 34

Save As directory dialog box 68Save As Text dialog box 69Save As… command 65, 67–69, 115Save command 67scale

FFT display 95logarithmic 95moving 49overlaid pages 56, 91setting 49stretching 49

Scale pop-up menu 15, 48, 94Scope Options dialog box 103Scope window 13–17

printing 76Scope Window command 13Scrolling button 14, 55section symbol, § 50selecting data 62–63selecting unit names 32Selection command 63selection information 90Selection miniwindow 63Set Background command 86Set Marker Position dialog box 85Set Scale dialog box 48Set Scale… option 48Set Selection dialog box 63settings 67, 68, 108settings file 68

148 Scope Software

Row button 87

SSample control 34Sampling dialog box 34sampling frequency 104sampling rate 22–24sampling speeds

computed functions 96stimulus waveform 103

Sampling… command 33

Setup menu 126Output Voltage… command 42Sampling… command 33Stimulator… command 37

Shift 97shifting waveforms 97Show Clipboard command 67Show Overlay command 55signal input controls 27single sweeps 33single-sided display 48

size control 13slider bar 39slope 90, 142Smooth 97, 140Source pop-up menu 35Speak Message dialog box 120Speak Message… command 119special access 108–109Special Access dialog box 108, 109special characters 49Square 99Start button 16Start pop-up menu 36Start Recording command 111Start-Up Settings dialog box 107Start-Up… command 107statistics 89Stim panel 42Stim Panel increment dialog boxes 42stimulation

and triggering 36, 37, 43, 44stimulator 37–44Stimulator Constant Output dialog box 42Stimulator dialog box 38Stimulator External Trigger 38Stimulator External Trigger dialog box 44Stimulator output 42Stimulator… command 37

Subtract 98Subtract Background command 86superimposed sweeps 34superscripts and subscripts 32, 50, 88sweep

Average 34Multiple 34Repetitive 34Single 33Superimpose 34

sweepscontrols 17, 33–35definition 33synchronising 36

system configuration information 132

Ttear-off data displays 90technical support 131–132Text button 39text file 68–69, 71–73Time axis 15Time Base panel 15, 22, 104time per division 104time per sweep 104title bar 13Trace Indicator 18transferring data 65–66Triangle stimulus waveform 38Trigger Marker 37

Index 149

Stimulus Page control 41stimulus waveform

Double 38Free Form 38, 40–41Multiple 38Pulse 38Ramp 38Triangle 38Up & Down 38

stimulus waveformsdisplay 53overlaying 53sampling speed 103storing 41

triggering 33, 36–37after the event 36and stimulation 36, 37, 43, 44before the event 36changing in Scope window 37external 35, 43, 44from signal 35Input A or Input B 35line 35slope 36synchronising recording 36user 35wih Start button 35

triggering event 35turn off input 24

Uunderscore symbol, _ 50Undo command 64, 65uninstalling software 3unit names 33Unit pop-up menu 32units conversion 28, 29–33, 48, 49

calibration 31typing in values 30using sampled data 30–32

Units Conversion dialog box 29units of computed functions 96Up & Down stimulus waveform 38Update Screen command 116

WWait… command 117Waveform buttons 52Waveform Cursor 58, 82, 93, 104Waveform Print Layout buttons 73where to start 2window

Data Pad 87Notebook 79Scope 13–17Zoom 56–59

Zzero reference point 820dB Reference Level dialog box 94Zoom window 56–59Zoom Window command 56

150 Scope Software

Windows menu 127Add to Data Pad command 88Data Pad command 87Marker command 84Notebook command 78Scope Window command 13Selection command 63Zoom Window command 56

Windows to Macintosh 11

XX–Y display 92–93

settings 52, 53

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License &

Copyright and Trademarks

e-corder and PowerChrom are registered trademarks, and EChem a trademark of of eDAQ Pty Ltd. Chart and Scope are trademarks of ADInstruments Pty Ltd and are used bt eDAQ under license. All eDAQ software, hardware, and documentation is protected by copyright. eDAQ retains the exclusive ownership of the trademarks and registered trademarks represented by its company name, logo, and product names.

Responsibilities

You and any others using any eDAQ product agree to use it in a sensible manner for purposes for which it is suited, and agree to take responsibility for their actions and the results of their actions.

If problems arise with an eDAQ product, eDAQ will

Software

all reasonable efforts to fix them. This service cur a charge, depending on the nature of the ms, and is subject to the other conditions in reement.

ware Warranty

Pty Ltd warrants e-corder systems, to be free ects in material and workmanship for one year he date of purchase. eDAQ Pty Ltd will repair lace defective equipment as appropriate.

tain a warranty repair/replacement you must tify us before return of the instrument and we

Warranty

will issue you with a RAN (return authorization number). You must ship the defective product at your expense. We will pay return shipping. The product should be packed safely (preferably in its original packaging) and have the RAN on the shipping label. Returns sent without a RAN may be refused delivery.

This warranty does not cover hardware that has:

• been modified by the user in any way;

• been subjected to unusual physical, electrical, or environmental stress. This includes damage due to faulty power sockets, inadequate earthing, or power spikes or surges;

• been damaged because of incorrect wiring to ancillary equipment, or because of substandard, connectors or cables; or

• had the original identification marks removed
or altered.
Software License

You have the non-exclusive right to use the supplied Scope software. (Your employees or students, for example, are entitled to use it, provided they adhere to this agreement.) Each separate purchase of the Scope software licenses it to be used on two computers at any given time (on one computer for data acquisition with an e-corder hardware unit, and on a second computer for the analysis of existing data files). Although multiple copies of a program may exist on several computers, more than

two copies must not be used simultaneously. Departmental/company licences are available if you wish to run more than two copies simultaneously.

Technical Support

Please register your unit to receive technical support. Technical assistance is available via email. Please describe the problem with as much detail as possible. Include a small example data file, if appropriate. Please also state:

• the model and serial number of your e-corder unit.

• the type of computer and operating system being used (for example Windows XP, or Macintosh OS 10.2)

• the software version you are using (for example Scope v4.0.1)

We endeavor to answer all your questions, but in some cases, for example where the problem relates to the other equipment that you are using, a nominal fee may be charged.

Jurisdiction

eDAQ Pty Ltd is bound by the laws of New South Wales in Australia, and any proceedings shall be heard by the Supreme Court of New South Wales in Australia.

Disclaimer

152

eDAQ reserves the right to alter specifications of hardware and software without notice.

No liability can be accepted for consequential damages resulting from use of eDAQ products.

Scope Software

Scope Software Manual

Documents