1. A. Virtual Instruments (VIs)
Virtual Instrument (VI) – A LabVIEW program
The appearance and operation of VIs imitate physical instruments, such as oscilloscopes and digital multimeters.

2. B. Parts of a VI
LabVIEW VIs contain three main components: 1. Front Panel 2. Block Diagram 3. Icon/Connector Pane

3. B. Parts of a VI – Front Panel
Front Panel – User interface for the VI
You build the front panel with controls (inputs) and indicators (outputs)
Just discuss how a front panel is the user interface of the VI and contains controls and indicators. A section following this slide concentrates on the front panel in more depth.

4. B. Parts of a VI – Block Diagram
Block Diagram – Contains the graphical source code
Front panel objects appear as terminals on the block diagram

5. 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

6. 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

7. E. Front Panel – Controls & Indicators
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

8. E. Front Panel – Numeric Controls/Indicators
The numeric data type can represent numbers of various types, such as integer or real
Numeric Control
Increment/Decrement Buttons
In the next few slides, you discuss basic data types: numerics, strings and Booleans. Discuss only front panel information here, such as appearance and what type of data you put in the control/indicator.
You will discuss representation, mechanical action, and string display types in the next lesson.
Numeric Indicator

9. 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
You will discuss the use of Booleans later, just talk about what they are here.
Boolean
Control
Boolean
Indicator

10. 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
Display types covered later. Just cover the basic concept here.

11. 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

12. 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

13. E. Front Panel – Configure Multiple Objects
Select multiple objects to simultaneously configure shared properties

14. Configuring Your LabVIEW Environment
Functions Palette
Tack the Functions palette and select Customize»Change Visible Categories then click Select All
Controls Palette
Tack the Controls palette and select Customize»Change Visible Categories then click Select All

15. Pratice
Replicate the following front panel

16. F. Block Diagram Terminals SubVIs Functions Constants Structures Wires
Block diagram objects include the following:
Terminals
SubVIs
Functions
Constants
Structures
Wires

17. 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
If you would like to, this is an excellent place to have your students change the view type of the terminal.

18. F. Block Diagram Terminals
Discuss the visual difference between controls and indicators on the block diagram, and discuss the difference in operation between controls, constants and indicators. Especially that constants are only available on the block diagram.
Right-click to change...

19. B. LabVIEW Data Types – Terminals
Terminals visually communicate information about the data type represented
Show that datatype is represented by the color, orange here, and the text on the terminal, DBL here.

20. 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
DBL Numeric Integer Numeric String
Scalar
1D Array
2D Array

21. 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
Nodes

22. 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

23. Practice
Look and the block diagram of the previous practice and add the following nodes:
Add
Multiply
Random number
Greater than
Less than
Get date/time in seconds
Then use wires to connect all the elements of the block diagram leaving no terminal unconnected.
Target:
Simulate a given temperature value, add a random noise of given amplitude, then light up an alert when such a temperature is greater than setpoint and another if is less than setpoint .

24. Practice solution

25. 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

26. 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
This is where you describe what a subVI is. In lesson 7, the student will learn how to build a subVI, but should already be very familiar with what they are, and how to use them.

27. 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
DBL Numeric Integer Numeric String
Scalar
1D Array
2D Array

28. B. LabVIEW Data Types – Terminals
Terminals visually communicate information about the data type represented
Show that datatype is represented by the color, orange here, and the text on the terminal, DBL here.

29. B. 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 Representation from the shortcut menu
Students learned about the numeric, Boolean and string datatype in Lesson 2. Now, they learn about implementing these datatypes, such as representation, Boolean action, and string display type. They will also learn a couple new datatypes: Enum and dynamic.
Here, talk about the difference between integers, floating point, etc...

30. B. 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

31. 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.
Have all students open this example program and experiment with it as you demonstrate.

32. B. 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

33. B. 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

34. B. 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
Point out that the datatype of the terminal is blue, showing that it is passing an integer

35. B. 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

36. F. Block Diagram – Wiring Tips
Press <Ctrl>-B to delete all broken wires
Right-click and select Clean Up Wire to reroute the wire

37. F. Block Diagram – Wiring Tips
Use the Clean Up Diagram tool to reroute multiple wires and objects to improve readability
Select a section of your block diagram
Click the Clean Up Diagram button on the block diagram toolbar

38. 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
Notes for instructing:
LabVIEW is NOT control flow. Visual Basic, C++, JAVA, and most other text-based programming languages follow a control flow model of program execution.
Sequential order of program elements determines execution order.
LabVIEW follows a dataflow model for running VIs.
A block diagram node executes when it receives all required inputs.
When a node executes, it produces output data and passes the data to the next node in the dataflow path.
The movement of data through the nodes determines the execution order of the VIs and functions on the block diagram.

39. I. Dataflow – Quiz Which node executes first? Add Subtract
Random Number
Divide
Sine
There is no right answer to this quiz, but there are some wrong answers. This quiz is intended to encourage students to think about dataflow and its implications...

40. I. Dataflow – Quiz Answers
NO CORRECT ANSWER
Which node executes first?
Add – possibly
Subtract – definitely not
Random Number – possibly
Divide – possibly
Sine – definitely not

41. Summary—Quiz Which function executes first: Add or Subtract? Add
Unknown
The answer is a.

42. Summary—Quiz Answer Which function executes first: Add or Subtract?
Unknown
The answer is a.

43. I. Case Structures Have two or more subdiagrams or cases
Execute and displays only one case at a time
An input value determines which subdiagram to execute
Similar to case statements or if...then...else statements in text-based programming languages

44. I. Case Structures
Case Selector Label: contains the name of the current case and decrement and increment buttons on each side
Selector Terminal: Wire an input value, or selector, to determine which case executes

45. Practice
Add to the previous practice a button in order to update the string label ONLY if the button is pressed. Then run. Change its mechanical action and run again. Create a enum control with items “Heating”, “Cooling”, “Conditioning” and use its values to turn on label “too hot” only, label “too cold” only, or both, according to the case selected. Make the string indicator display “Hi there!” if the user inputs “Hello”, or the same input string if otherwise.

46. I. Case Structures – Default Case
You can specify a default case for the Case structure
If you specified cases for 1, 2, and 3, but you get an input of 4, the Case structure executes the default case
Right-click the Case structure border to add, duplicate, remove, or rearrange cases and to select a default case

47. I. Case Structures – Input & Output Tunnels
You can create multiple input and output tunnels
Inputs are available to all cases if needed
You must define each output tunnel for each case
Point out difference between tunnels that have been wired for all cases, and tunnels that have not.

48. I. Case Structures – Use Default if Unwired
Default values are:
Avoid using the Use Default If Unwired option on Case structure tunnels
Adds a level of complexity to your code
Complicates debugging your code
Data Type
Default Value
Numeric
Boolean
FALSE
String
Empty

49. I. Case Structures – Boolean
Boolean input creates two cases: True and False

50. I. Case Structures – Integer
Add a case for each integer as necessary
Integers without a defined case use the default case

51. I. Case Structures – String
Add a case for each string as necessary
Strings without a defined case use the default case

52. I. Case Structures – Enum
Gives users a list of items from which to select
The case selector displays a case for each item in the enumerated type control

53. I. Case Structures - Error Checking and Error Handling
Use Case Structures inside VIs to execute the code if there is no error and skip the code if there is an error