Charts&Graphs

CHARTS AND GRAPHS

Prepared By: Shivraj Rathod Devendra Shetye

VEERMATA JIJABAI TECHNOLOGICAL INSTITUTE MATUNGA, MUMBAI 400019

Guided By: Dr.M.S.Panse

Introduction1. Charts & graphs provide a great deal of visual appeal. 2. They allow users to quickly spot trends, examine pronounced

data, and see an actual picture. 3. Charts & graphs can be used

• To represent data, illustrate important patterns or relationships.

• Observe changes as data is altered.

• Provide a visual representation of data.

• Effectively clarify information.

• Represent many different types of data.

• Allow users to perceive information quickly.

Presenting your Results in VI

1. Displaying Data on the Front Panel• Controls and Indicators

• Graphs and Charts

• Loop Timing

2. Signal Processing• Math Script

• Arrays

• Clusters

• Waveforms

Fig.1-The Virtual Instrumentation Approach

1. The waveform chart is a special numeric indicator that displays one or more plots.

2. The waveform chart is located on the Controls >> Graphs >> Waveform Chart.

3. Waveform charts can display single or multiple plots.4. Waveform Charts update modes

• Strip chart -shows running data continuously scrolling from left to right across the chart.• Scope chart -shows one item of data, such as a pulse or wave, scrolling partway across the chart from left to the right.• Sweep chart- works similarly to a scope except it shows the old data on the right and the new data on the left separated by a vertical line.

Waveform Charts

Waveform Charts

Selected from the Controls Palette » Graphs » Waveform Charts Palette Waveform Charts update modes- Waveform Chart » Advance » Update Mode » Strip/Scope/Sweep Chart.

1. You can wire a scalar output directly to a waveform chart or display multiple plots.

2. Bundle multiple plots together using the Bundle function located on the Functions » Cluster palette.

3. The Bundle function bundles multiple outputs to plot on the waveform chart.

4. The waveform chart terminal changes to match the output of the Bundle function.

5. To add more plots, use the Positioning tool to resize the Bundle function.

Wiring Data into Charts

Single Plot Charts Multi Plot Charts

8

Modifying Chart Properties

• Change the appearance

• Set the format and precision of the axis

• Choose the plot type

• Edit the scales

• Document the chart

9

Customizing Charts and Graphs

Right-click and select Visible Items to view the following items:

• Plot Legend

• Digital Display

• Scrollbar

• X and Y Scale

• Graph Palette

• Scale Legend

Graph Palette

Scale Legend

Zoom Subpalette

Charts – Add 1 data point at a time with history

• Chart updates with each individual point it receives

Functions » Express » Graph Indicators » Chart

Example-1

To construct a VI to study different types of Charts

Strip Chart Scope Chart Sweep Chart

Example-2

This VI illustrates how to programmatically clear different types of charts.

Charts can accept a single point at a time or multiple points

at a time. The charts are cleared by writing empty arrays to the History

Data property node.

Graphs in VI

Outline

Basics Differences between Charts and Graphs Different Types of Graphs Examples in LabVIEW

GRAPH It displays one or more plots of sampled measurements.

It can plot single-valued/Multivalued functions with points uniformly/non-uniformly distributed along the x-axis.

It can display plots containing any number of points. It also accepts several data types, which minimizes the extent

to which you must manipulate data before you display it.

Differences between Waveform Chart and Waveform Graph

Waveform Graph Waveform ChartThis is for offline display. (i.e. data is already acquired and stored.)

This is for online display. (i.e. real time data )

Does not have History; thus Arrays and clusters are essential.

It has History.

Initial point and interval of the x-axis can be specified using ‘Bundle’.

Waveform Chart does not allow this.

‘Build Array’ can be used to combine multiple channels of data to display them together on single Waveform Graph.

‘Bundle’ is used for multiple channel data display on single Waveform Chart.

Displays data row-wise. Displays data column-wise.

Types of Graphs

Type Description

Waveform Graphs

Display data typically acquired at a constant rate.

XY Graphs Display data acquired at a non-constant rate and data for multivalued functions.

Intensity Graphs

Display 3D data on a 2D plot by using color

to display the values of the third dimension.

Digital Waveform Graphs

Display data as pulses or groups of digital lines

Types of Graphs

Type Description

Mixed Signal Graphs Display data types accepted by waveform graphs, XY graphs, and digital waveform graphs. Also accept clusters that contain any combination of those data types.

2D Graphs Display 2D data on a 2D front panel plot.

3D Graphs Display 3D data on a 3D front panel plot.

ActiveX 3D Graphs 3D data on a 3D plot in an ActiveX object on the front panel.

Note: 3D and ActiveX 3D graph controls are supported only on Windows in the LabVIEW Full and Professional Development Systems.

Waveform Graph

Chart plots data point by point, whereas Graph plots it all at once.

X-axis data is uniformly spaced.

Arrays and Clusters play important role while using Graphs.

Graphs and Loops

Front Panel and Block Diagram of VI to send same Array data to both Chart and Graph

The Front Panel after one cycle through the WHILE Loop

The Front Panel after multiple cycles through the WHILE Loop

Waveform Graph- Single and Multiple plots

For Single plot, Initial point and interval of the x-axis can be specified using ‘Bundle’.

The waveform graph accepts an array of clusters of an x value, a delta x value, and an array of y data. This is the most general of the multiple-plot waveform graph data types.

XY Graph

To plot data for given (uniformly/non-uniformly spaced) x-axis values.

‘Bundle’ is used for a single channel display.

‘Build Array’ is used after ‘Bundle’ for multiple channel display.

Intensity Graph

Used to display 3D data on a 2D plot by placing a block of colors on a Cartesian plane.

Eg.To display patterned data such as temperature pattern and terrains.

The rows of the data pass into the display as new columns on the graph

Intensity graph

Digital Waveform Graph

Digital Waveform Graph

Digital Waveform Graph

Upon Expanding Digital Buses on Y Axis

Mixed Signal Graph

Thank You

REFERENCES

Ronald W. Larsen,(Copyright-2011),”LabVIEW for Engineers”,Prentice Hall Publications(ISBN-13: 978-0-13-609429-6 (alk. paper),ISBN-10: 0-13-609429-5 (alk. paper))

Sanjay Gupta and Joseph John, second edition- Fifth reprint 2013,”Virtual Instrumentation using LabVIEW”, McGraw Hill Education(India),ISBN:978-0-07-070028-4

LabVIEW Introduction Course Manual available at www.ni.com.

Examples available in ‘LabVIEW 2013 HELP’.