Ni.com/training LabVIEW Workshop #1 Diego Torres LabVIEW Student Ambassador Fall 2011 ITESM CQ.

ni.com/training

LabVIEW Workshop #1

Diego TorresLabVIEW Student Ambassador

Fall 2011ITESM CQ

TOPICS

ni.com/training

A. Compiled graphical development environmentB. Development time reduction of four to ten timesC. Tools to acquire, analyze, and present your data

What is LabVIEW?Laboratory Virtual Instrumentation Engineering Workbench

TOPICS

ni.com/training

Navigating LabVIEW

A. Virtual Instruments (VIs)B. Parts of a VIC. Starting a VID. Project ExplorerE. Front PanelF. Block Diagram

G. Searching for Controls, VIs and Functions

H. Selecting a ToolI. DataflowJ. Polymorphism

3

ni.com/training

A. Virtual Instruments (VIs)

The appearance and operation of VIs imitate physical instruments, such as oscilloscopes and digital multimeters.

4

Virtual Instrument (VI) – A LabVIEW program

ni.com/training

B. Parts of a VI

LabVIEW VIs contain three main components:1. Front Panel 2. Block Diagram 3. Icon/Connector Pane

5

ni.com/training

B. Parts of a VI – Front Panel

You build the front panel with controls (inputs) and indicators (outputs)

6

Front Panel – User interface for the VI

ni.com/training

B. Parts of a VI – Block Diagram

Front panel objects appear as terminals on the block diagram

7

Block Diagram – Contains the graphical source code

ni.com/training

B. Parts of a VI – Icon/Connector Pane

• Icon: graphical representation of a VI• Connector Pane: map of the inputs and outputs of a VI• Icons and connector panes are necessary to use a VI as

a subVI− A subVI is a VI that is inside of another VI− Similar to a function in a text-based programming

language Icon Connector Pane

8

DEMONSTRATION

C. Starting a VI

Demonstrate using the Getting Started dialog box and the New dialog box to start a VI.

ni.com/training

D. Project Explorer

Use LabVIEW Projects to:• Group LabVIEW files and non-LabVIEW files• Create build specifications• Deploy or download files to targets

10

DEMONSTRATION

Using the Project Explorer

Demonstrate creating a project, adding files, and removing files.

ni.com/training

E. Front Panel – Controls Palette

• Contains the controls and indicators you use to create the front panel

• Access from the front panel by selecting View»Controls Palette

12

ni.com/training

E. Front Panel – Front Panel Toolbar

13

ni.com/training

E. Front Panel – Controls & Indicators

• Controls− Knobs, push buttons, dials, and other input devices− Simulate instrument input devices and supply data to the block

diagram of the VI• Indicators

− Graphs, LEDs, and other displays− Simulate instrument output devices and display data the block

diagram acquires or generates

14

ni.com/training

E. Front Panel – Numeric Controls/Indicators

The numeric data type can represent numbers of various types, such as integer or real

15

Numeric Indicator

Numeric Control

Increment/Decrement Buttons

ni.com/training

E. Front Panel – Boolean Controls/Indicators

• The Boolean data type represents data that only has two parts, such as True and False or On and Off• Use Boolean controls and indicators to enter and display

Boolean (True or False) values• Boolean objects simulate switches, push buttons, and LEDs

16

BooleanControl

BooleanIndicator

ni.com/training

E. Front Panel – Strings

• The string data type is a sequence of ASCII characters • Use string controls to receive text from the user such as a

password or user name• Use string indicators to display text to the user

17

ni.com/training

LabVIEW Data Types – Terminals

Terminals visually communicate information about the data type represented

ni.com/training

LabVIEW Data Types – Numerics

• The numeric data type represents numbers of various types• To change the representation

of a numeric, right-click the control, indicator, or constant, and select Representationfrom the shortcut menu

ni.com/training

LabVIEW Data Types – Boolean

• Behavior of Boolean controls is specified by the mechanical action• In LabVIEW, the Boolean

data type is represented with the color green

ni.com/training

Mechanical Action of Booleans

Use the Mechanical Action of Booleans VI located in the NI Example Finder to learn about the different switch and latch actions.

ni.com/training

Data Types – String

• A sequence of displayable or non-displayable ASCII characters• On the front panel, strings appear as tables,

text entry boxes, and labels• Change the display type from the short-cut

menu: Normal, ‘\’ Codes, Password and Hex• Edit and manipulate strings with the String functions on the

block diagram• In LabVIEW, the string data type is represented with the color

pink

ni.com/training

Data Types – Enum

An enum represents a pair of values, a string and a numeric, where the enum can be one of a defined list of values

ni.com/training

Data Types – Enum

• Enum: enumerated control, constant, or indicator• Enums are useful because it is easier

to manipulate numbers than strings on the block diagram

ni.com/training

Data Types – Dynamic

• Stores the information generated or acquired by an Express VI• Non-Express VIs do not accept the dynamic data type

− To use a built-in VI or function to analyze or process the dynamic data type, you must convert the data type

− Numeric, waveform, or Boolean data indicators or inputs automatically convert the dynamic data type when wired

• In LabVIEW, the dynamic data type is represented with the color dark blue

ni.com/training

E. Front Panel – Shortcut Menus

• All LabVIEW objects have associated shortcut menus

• As you create a VI, use the shortcut menu items to change the look or behavior of front panel and block diagram objects

• To access the shortcut menu, right-click the object

26

ni.com/training

E. Front Panel – Property Dialog Box

• Right-click a front panel object and select Properties to display

• The options available on the property dialog box are similar to the options available on the shortcut menu for that object

27

ni.com/training

E. Front Panel – Configure Multiple Objects

• Select multiple objects to simultaneously configure shared properties

28

ni.com/training

F. Block Diagram

Block diagram objects include the following:

• Terminals• SubVIs• Functions• Constants• Structures• Wires

29

ni.com/training

F. Block Diagram – Functions Palette

Contains the VIs, functions, and constants you use to create the block diagram

30

ni.com/training

F. Block Diagram – Block Diagram Toolbar

31

ni.com/training

F. Block Diagram – Terminals

• Terminals are:− Block diagram appearance of front panel objects− Entry and exit ports that exchange information between the

front panel and block diagram− Analogous to parameters and constants in text-based

programming languages• Change the view type of a terminal by toggling the View as

Icon selection from the context menu

32

ni.com/training

F. Block Diagram Terminals

33

ni.com/training

F. Block Diagram – Nodes

• Objects on the block diagram that have inputs and/or outputs and perform operations when a VI runs• Analogous to statements, operators, functions, and

subroutines in text-based programming languages• Nodes can be functions, subVIs, or structures

34

Nodes

ni.com/training

F. Block Diagram – Function Nodes

• Fundamental operating elements of LabVIEW• Do not have front panels or block diagrams, but do have

connector panes• Double-clicking a function only selects the function – does

not open it like a VI• Has a pale yellow background on its icon

35

ni.com/training

F. Block Diagram – SubVI Nodes

• SubVI: VIs that you build to use inside of another VI• Any VI has the potential to be used as a subVI• When you double-click a subVI on the block diagram, you

can view the front panel and block diagram of the subVI− The upper right corner of the front panel and block diagram

displays the icon for the current VI− This is the icon that appears when you place the VI on a block

diagram as a subVI

36

ni.com/training

F. Block Diagram – SubVI Nodes

• Express VIs are a special type of subVI− Require minimal wiring because you configure them

with dialog boxes− Save the configuration of an Express VI as a subVI• Icons for Express VIs appear on the block diagram

as icons surrounded by a blue field

37

ni.com/training

F. Block Diagram – Icons/Expandable Nodes

38

ni.com/training

F. Block Diagram – Wires

• Transfer data between block diagram objects through wires• Wires are different colors, styles, and thicknesses,

depending on their data types• A broken wire appears as a dashed

black line with a red X in the middle

39

Scalar1D Array2D Array

DBL Numeric Integer Numeric String

ni.com/training

F. Block Diagram – Wiring Tips

• Press <Ctrl>-B to delete all broken wires• Right-click and select Clean Up Wire to reroute the wire

40

ni.com/training

F. Block Diagram – Wiring Tips

Use the Clean Up Diagram tool to reroute multiple wires and objects to improve readability

1. Select a section of your block diagram2. Click the Clean Up Diagram button on the block diagram

toolbar

41

GOAL

Exercise 2-1Concept: Exploring a VI

Identify the parts of an existing VI.

DISCUSSION

Exercise 2-1Concept: Exploring a VI

• What are constants and when should you use them?• What are free labels and when should you use them?

ni.com/training

G. Searching for Controls, VIs & Functions

Find controls, functions, and VIs using the Search button on the Controls and Functions palette.

44

ni.com/training

G. Global Search

The Search bar in the top right of the Front Panel and Block Diagram windows can be used to search the palettes, help, and ni.com.

45

GOAL

Exercise 2-2Concept: Navigating Palettes

Learn to use the palettes and search for controls, functions and VIs.

DISCUSSION

Exercise 2-2Concept: Navigating Palettes

• Why would you want to add a function to the Favorites category in the Functions palette?

ni.com/training

H. Selecting A Tool

• Create, modify, and debug VIs using the tools provided by LabVIEW• A tool is a special operating mode of the

mouse cursor• The operating mode of the cursor corresponds to the icon of

the tool selected• When using the Automatic Tool Selection, LabVIEW

chooses which tool to select based on the current location of the mouse

48

GOAL

Exercise 2-3Concept: Selecting A Tool

Gain experience using the Automatic Tool Selection to select which tool to use.

DISCUSSION

Exercise 2-3Concept: Selecting A Tool

• How do you enable automatic tool selection?

ni.com/training

I. Dataflow

LabVIEW follows a dataflow model for running VIs• A node executes only when data are available at all of its

input terminals• A node supplies data to the output terminals only when the

node finishes execution

51

ni.com/training

I. Dataflow – Quiz

Which node executes first? a) Addb) Subtractc) Random Numberd) Divide e) Sine

52

ni.com/training

I. Dataflow – Quiz Answers

NO CORRECT ANSWER

Which node executes first? a) Add – possiblyb) Subtract – definitely notc) Random Number – possiblyd) Divide – possiblye) Sine – definitely not

53

GOAL

Exercise 2-4Concept: Dataflow

Understand how dataflow determines the execution order in a VI.

DISCUSSION

Exercise 2-4Concept: Dataflow

• Should a well-designed block diagram flow in a particular direction?

ni.com/training

J. Polymorphism

Definition: a programming language feature that allows values of different data types to be handled using a uniform interface.

In LabVIEW: the ability of VIs and functions to automatically adapt to accept input data of different data types

i.e. Numeric Functions Useful when performing the same

operation on different data types

ni.com/training

Summary—Quiz

1. Which function executes first: Add or Subtract?a) Addb) Subtractc) Unknown

57

ni.com/training

Summary—Quiz Answer

1. Which function executes first: Add or Subtract?a) Addb) Subtractc) Unknown

58

ni.com/training

Summary—Quiz

2. Which function executes first: Sine or Divide?a) Sineb) Dividec) Unknown

59

ni.com/training

Summary—Quiz Answer

2. Which function executes first: Sine or Divide?a) Sineb) Dividec) Unknown

60

ni.com/training

Summary—Quiz

3. Which of the following functions executes first: Random Number, Add or Divide?a) Random Numberb) Dividec) Addd) Unknown

61

ni.com/training

Summary—Quiz Answer

3. Which of the following functions executes first: Random Number, Add or Divide?a) Random Numberb) Dividec) Addd) Unknown

62

ni.com/training

Summary—Quiz

4. Which of the following functions execute last: Random Number, Subtract or Add?a) Random Numberb) Subtractc) Addd) Unknown

63

ni.com/training

Summary—Quiz Answer

4. Which of the following functions execute last: Random Number, Subtract or Add?a) Random Numberb) Subtractc) Addd) Unknown

64

ni.com/training

Summary—Quiz

5. What are the three parts of a VI?a) Front Panelb) Block Diagramc) Projectd) Icon/Connector Pane

65

ni.com/training

Summary—Quiz Answer

5. What are the three parts of a VI?a) Front Panelb) Block Diagramc) Projectd) Icon/Connector Pane

66