Virtual Instruments:

Parts of a LabVIEW Program

LabVIEW Core 1, Module 1
 Agenda
Introduction to LabVIEW
Parts of a LabVIEW Program
What is a VI?
Creating a VI
What are the parts of a VI?
Quiz
Exercise
 Introduction to LabVIEW
LabVIEW is a graphical programming
language.
One of its greatest strengths is how intuitive it
is.
It can be used to create sophisticated
programs with elegant user interfaces quickly
and easily.
 What is a VI?
The appearance and operation of VIs imitate
physical instruments, such as oscilloscopes
and digital multimeters.
 Creating a VI
Demo:
Start LabVIEW, Getting Started Window,
Open a VI using:
Most recent VI (File menu)
Open section or File-Open menu
Manual creation:
New section or File-New menu
Create from a template
 What are the parts of a VI?
Demo
Use the Example Finder to open example code
Analyzing and processing signals section
Interpolation section
Open 1D fourier interpolation.vi
 What are the parts of a VI?
Front Panel, Block Diagram, Connector Pane
Controls and Indicators are the Input and output
Open the block diagram using Show block
diagram
Crtl + E and to toggle
Block diagram:
contains the graphical source code of the program
 What are the parts of a VI?
Front panel objects:
appear on the block diagram as terminals
Icon:
is a graphical representation of a VI
Connector pane:
is a map of the inputs and outputs of a VI and it allows
a user to use and view a VI as a subVI.
A subVI is a VI that is found inside another VI
Similar to a function in a text based programming language
 Quiz
What does VI stand for?
a) Visual Instrument
b) Virtual Instance
c) Virtual Instrument
d) Virtual Interface
 Quiz
What part of a VI interacts with the user?
a) Block Diagram
b) Connector Pane
c) Icon
d) Front Panel
 Quiz
What are the three steps that can be used to
effectively create simple data acquisition
application?
a) Display, present, store
b) Input, output, process
c) Read , interpret, store
d) Acquire, analyze, present
 Quiz
Which two methods open the Block Diagram?
a) Ctrl-B and Window-Show Diagram
b) Ctrl-E and File-Display Block Diagram
c) Ctrl-E and Window-Show Block Diagram
d) Ctrl-B and File-Display Block Diagram
 Quiz
Which of these is a great resource for finding
pre-written code on an unfamiliar topic?
a) A new blank project
b) The Example Finder
c) The Front Panel
d) The Project Manager
 Exercise
Complete the exercise:
LV1M1_Virtual Instruments
provided inside the moodle course!

Investigate the front panel and block diagram

concepts in more detail!
Projects: Creating LabVIEW
Project Files
LabVIEW Core 1, Module 2
 Agenda
What is a LabVIEW project?
Using the Project Explorer to organize our files
Creating, using, and saving a LabVIEW project
 What is a LabVIEW Project?
A type of file used to group together both
LabVIEW and non-LabVIEW files
Used to create build specifications and deploy
to targets
A LabVIEW project must be used when
building applications and shared libraries
Great for organizing and tracking files
 What is a LabVIEW Project?
Creates an .lvproj file
Contains references to files within the
LabVIEW project
Used to work with real-time devices, field-
programmable gate arrays, or personal digital
assistant devices.
Using the Project Explorer to organize
our files
Demo
Open Project Explorer (Open Existing or File-Open Project)
Project Explorer Window
create and edit
Items page
Project Tree
Files page
Files on disk
Default Items
My Computer, Dependencies, Build Specifications
Toolbars
Various operations
Creating, using and saving a LabVIEW
project
Demo
Create a new LabVIEW project (Create Project, File-Create
Projects)
Blank Project or Template
Add Items to it
Add file to project
Folders within a LabVIEW project
Virtual Folder (add Virtual Folder)
Snapshot (add Snapshot Folder)
Auto-populating (add Auto-populating Folder)
Add new VI to project
File-Save Project
 Quiz
Which type of folder always contains the
current contents of the actual folder?
a) VI
b) Auto-populating
c) Snapshot
d) My Computer
 Quiz
Which type of folder shows only the contents
of the actual folder at time of creation?
a) VI
b) Auto-populating
c) Snapshot
d) My Computer
 Quiz
Why would we use projects in LabVIEW?
a) To increase the speed of the program
b) To make our programs organized and easy to
keep track of a large application
c) To separate front panels from block diagrams
d) To provide an interface with connected
hardware
 Quiz
A LabVIEW Project allows us to group together
both LabVIEW and non-LabVIEW files.
a) True
b) False
 Quiz
What is the file extension of a LabVIEW
project file?
a) .vi
b) .proj
c) .viproj
d) .lvproj
 Exercise
Complete the exercise:
LV1M2_Projects
provided inside the moodle course!

In the exercise for this module, you will create

and modify a LabVIEW project.
Front Panel: Defining
the User Interface
LabVIEW Core 1, Module 3
 Agenda
What is the front panel?
What is the controls palette?
What are controls and indicators?
Using menus, property dialog boxes, and the
front panel toolbar to customize the front
panel
 What is the front panel?
Demo:
Example Finder, Analysis, Signal Processing and
Mathematics -> Signal and Noise Generation ->
Arbitrary Wave Display
 What is the controls palette?
Demo:
File-New, Blank VI
View-Controls Palette or Right-Clicking on the
Front Panel
Grouped into categories
Search field: Slide (Vertical Fill Slide Numeric)
 What are controls and indicators?
Controls are the interactive inputs of a VI
Knobs, push buttons, dials,
They simulate instrument input devices as well as
supply data to the block diagram of the VI.
Indicators are the visual outputs of a VI
Numeric indicators, string indicators, graphs, LEDs,

Indicators simulate instrument output devices and
display data the block diagram acquires or
generates.
 What are controls and indicators?
Continue Demo
Numeric
Modern-Numeric-Numeric Control
Modern-Numeric Indicator
Boolean
Modern-Boolean-OK Button
Modern-Boolean-Square LED
String data
String and Path-String Control
String and Path-String Indicator
 Using menus, property dialog boxes, and the
front panel toolbar to customize the front panel
Continue Demo:
Right Click the Numeric Control
Visible Items
Properties
Data Type Tab (other module)
Documentation Tab (other module)
Appearance Tab (Label, Enabled State, Caption, Size, Show
Radix, Increment, Decrement Buttons)
Data Entry tab (Min, Max, Increment)
Display Format Tab (Float, Digits)
 Using menus, property dialog boxes, and the
front panel toolbar to customize the front panel
Continue Demo:
Front Panel Toolbar
Run Button (Unbroken, broken Error List Window)
Run Continuously Button
Abort Execution Button
Pause Button
Text settings
Align Objects
Distribute Objects
Resize Objects
Reorder Objects
Show Context Help Button (Ctrl-H)
 Quiz
Which type of data does an LED indicator
display?
a) Numeric
b) Boolean
c) String
d) Error
 Quiz
Which type of data does a knob control
output?
a) Numeric
b) Boolean
c) String
d) Error
 Quiz
What is the purpose of a front panel?
a) A representation of LabVIEW code
b) An organization of the VIs within a file
c) A user interface of a virtual instrument
d) To acquire data from hardware
 Quiz
What do you use when you cannot find a
control in the controls palette?
a) Press Ctrl-H
b) Look through all the options
c) Find a similar control
d) Use the search function
 Quiz
When you want to stop your program,
pressing the Abort Execution button is the
best thing to do.
a) True
b) False
 Exercise
Complete the exercise:
LV1M3_Front Panel
provided inside the moodle course!

Create a front panel using a variety of different

styles and types of controls and indicators.
Modify their properties, appearance, and layout.
 Block Diagram:
Writing LabVIEW Programs
LabVIEW Core 1, Module 4
 Agenda
What is the block diagram?
Using terminals on the block diagram
Using Functions palette and searching to build
a block diagram
What are nodes?
Using wires to make connections on the block
diagram
Using the block diagram toolbar
 What is the block diagram?
Demo:
Add_a_b_constant.vi
Block diagram is where we write the code of
the program
Terminals, subVIs, functions, constants, structures,
and wires
Window-Show Block diagram or Ctrl-E
 Using terminals on the block diagram
Objects on the front panel appear as terminals
on the block diagram
When the block diagram code executes and
reads the values from the terminals, they will
take on the values that the user has input on
the front panel.
Control, indicator, constants, and node terminals
Add function
 Using the functions palette and
searching to build a block diagram
Contains VIs, functions, and constants
View-Functions palette or right-clicking on the block
diagram
Thumb-tag to fix it to the screen
Categories od sub-palettes
Numeric, Boolean, String, Comparison
Structures
Search button
Equal to 0 comparison
Customize visible palettes
 What are nodes?
Nodes are objects on the block diagram which have inputs and/or
outputs and perform operations when a VI runs.
Statements, operators, functions and sub-routines in text-based
languages
Functions, subVIs or structures
We can essentially create our own functions by placing VIs inside of
other VIs.
subVIs
Write to Spreadsheet VI from File I/O Functions palette
Double-click it
Express VI
Configured using dialog boxes
Simulate Signal Express VI from the Express palette, Input
Expandable node, blue field
 Using wires to make connections on the block
diagram
Wires are of different colors, styles, and thicknesses, depending on
their data types.
Boolean wires are green
String wires are pink
Numeric wires can be blue or orange
Colors match the color of the terminal
When an output terminal is wired to an incompatible input
terminal, a broken wire appears.
Dashed black line with a red X in the middle
Write to Spreadsheet Path output to the Amplitude input of the
Express VI
Ctrl-B to delete all broken wires
Clean Up wire to reroute it or Clean Up Diagram tool (Ctrl-U, Ctrl-Z
to undo)
 Using the block diagram toolbar

Similar to the front panel toolbar with a few new

buttons
Highlight execution button to display an animation of
the block diagram when we run our VI to watch the
execution of the code.
Retain wire Values button to turn on or off the ability
to save the wire values at each point in the flow of
execution.
When placing a probe, we see the most recent value of the
data that has passed through the wire.
Step into, Step over, and Step out buttons (later
module)
 Quiz
The block diagram is where we write the code
for our program.
a) True
b) False
 Quiz
Which color is a numeric integer wire?
a) Blue
b) Green
c) Orange
d) Purple
 Quiz
Which color is a Boolean wire?
a) Blue
b) Green
c) Orange
d) Purple
 Quiz
What happens when incompatible terminals
are wired?
a) The wire turns solid red
b) A dialog box pops up to indicate that you have
made a mistake
c) The wire wont finish as LabVIEW will not allow
the terminal to be connected
d) The wire will appear as a dashed black line with
a red X in the middle
 Quiz
What is the easiest way to clean up a block
diagram?
a) Move all functions into better positions
b) Rewire all wires that cross
c) Save, exit, then reopen the VI
d) Press the Clean Up Diagram button in the
toolbar
 Exercise
Complete the exercise:
LV1M4_Block Diagram
provided inside the moodle course!

Create block diagram code, place functions, wire

controls and indicators to functions, and run
code.
 Block Diagram:
Selecting Tools
LabVIEW Core 1, Module 5
 Agenda
What is the Tools Palette?
Using the Tools Palette
 What is the Tools Palette?
Graphical nature of LabVIEW is a great
strength
Easy to create user-friendly interfaces
Simple to write graphical code
LabVIEW contains a multitude of tools to help
us create our VIs
 Using the Tools Palette
Demo: open and use the Tools Palette
Automatic Tool Selection Mode
If disabled: change tools manually using the Tab
key or the spacebar:
Tab key: cycle through most commonly used tools
Spacebar: toggle between the two most common tools
 Using the Tools Palette
Specific tools (enabled by Automatic Tool
Selection):
Operating tool: pointing finger
Positioning tool: arrow (Ctrl key for copying)
Labeling tool: for a free label double-click in any
open space
Wiring tool: manually wire terminals together
 Using the Tools Palette
Specific tools (not enabled by Automatic Tool
Selection):
Object Shortcut Menu tool
Scrolling tool
Breakpoint tool
Probe tool
Color copy and coloring tool
 Quiz
Where is the Tools Palette visible?
a) On the front panel
b) On the block diagram
c) On both the front panel and block diagram
d) On the Context Help window
 Quiz
With the Automatic Tool Selection enabled,
how can we add a free label to our code?
a) Right-click a control
b) Double-click a control
c) Press <Tab>
d) Double-click in an open area
 Quiz
Which of the following tools can be used to
click a button?
a) Operating tool
b) Positioning tool
c) Object Shortcut Menu tool
d) Probe tool
 Quiz
Which of the following tools can be used to
resize a control?
a) Operating tool
b) Positioning tool
c) Object Shortcut Menu tool
d) Probe tool
 Quiz
Which of the following tools is most useful
when we have a single button mouse?
a) Operating tool
b) Positioning tool
c) Object Shortcut Menu tool
d) Probe tool
 Exercise
Complete the exercise:
LV1M5_Selecting Tools
provided inside the moodle course!

Use various tools and Automatic Tool Selection

to interact with the front panel and block
diagram.
 Dataflow:
Code Execution Order
LabVIEW Core 1, Module 6
 Agenda
What is Dataflow?
Using Execution Highlighting
Programming with Dataflow
 What is Dataflow?
Dataflow is the model which defines the order
in which LabVIEW code executes.
Two Rules of Dataflow:
Nodes execute when they receive all of their
needed inputs.
When a node executes, it passes on output data
to the next node.
 Using Execution Highlighting
Demo: enable Execution Highlighting and
watch the data in a simple VI.
 Programming with Dataflow
Example: add two numbers together, subtract
50 from the result and display the final result
on the front panel.
Dataflow is similar to an assembly line: once
we receive our parts, we can complete our
task.
General guideline: create code that executes
from left to right
 Parallelism
Copy the numeric inputs
Create a multiply function and wire it to the
new numeric inputs
Copy the result terminal and wire it to the
output of the multiply function
Execute the code: will the add or the multiply
function execute first?
 Quiz
Where is the Highlight Execution button
located?
a) On the front panel toolbar
b) On the Controls palette
c) On the Functions palette
d) On the block diagram toolbar
 Quiz
How does execution highlighting affect how
the code runs?
a) It runs faster because more data flows through
the wires
b) It runs slower because data moves slower
c) It runs slower because it shows the flow of the
data at a human pace
d) It does not affect the speed at which the
program runs
 Quiz
If two segments of code are not connected by
a wire they are called:
a) Perpendicular
b) Orthogonal
c) Parallel
d) Coincident
 Quiz
When there are two parallel sets of code,
which will run first?
a) The one furthest to the left on the block diagram
b) The one furthest to the right on the block
diagram
c) The one furthest to the top on the block diagram
d) Indeterminate: it cannot be known which will
run first
 Exercise
Complete the exercise:
LV1M6_Dataflow
provided inside the moodle course!

Use mathematical calculations in parallel and in

series to demonstrate dataflow programming.
Programming a Simple VI

LabVIEW Core 1, Module 7

 Agenda
What is a Simple VI?
Creating a Simple VI
Exploring Other Express VIs
 What is a Simple VI?
In their simplest form, most Vis have three
main tasks:
Acquiring data
Analyzing the data
Presenting the result
 Creating a Simple VI
Exercise:
Express Palette Input Simulate Signal
Add noise checkbox Gaussian White Noise
Express Palette Signal Analysis Filter (Low pass)
Express Palette Signal Manipulation- Merge
Signals
Wire
Right-click output of Merge Signals Create Graph
Indicator
 Exploring Other Express VIs
Acquire task: DAQ Assistant, Simulate Signal,
Read from Measurement file.
Analyze task: Amplitude and Level
Measurements, Statistics, Tone
Measurements, etc.
Presenting task: Write to Measurement File,
Build Text, etc.
 Quiz
What does the merge signals function do to
the input signals?
a) Adds them together into one signal
b) Subtracts the top one from the bottom one
c) Multiplies them together
d) Puts them both together in the same wire
 Quiz
What are the three tasks of a typical VI?
a) Acquiring data, analyzing the data and
presenting the data
b) Functions, data, and computation
c) Data inquisition, interpretation, processing
d) Analyzing data, data flow, parallel loops
 Quiz
What does the DAQ Assistant do?
a) Generates a signal
b) Measures data from a DAQ device
c) Outputs data to a DAQ device
d) b&c
 Quiz
Where do you find Express VIs?
a) The Boolean category of the Functions palette
b) The Express category of the Controls palette
c) The Express category of the Functions palette
d) None of the above
 Quiz
Which Express VI would be most useful for
recording data for later use?
a) Read from Measurement File Express VI
b) Amplitude and Level Measurement Express VI
c) Statistics Express VI
d) Write to Measurement File Express VI
 Exercise
Complete the exercise:
LV1M7_Dataflow
provided inside the moodle course!

Create your own simple VI made from

LabVIEWs Express VIs.
 LabVIEW Help Utilities:
Getting Assistance Creating and
Editing VIs
LabVIEW Core 1, Module 8
 Agenda
Context Help
LabVIEW Help
NI Example Finder
 Context Help
Context Help displays basic information about
LabVIEW items
Bring up:
Show Context Help (Help menu)
Ctrl-H
SubVIs and functions: Window displays the
icon with terminal names and wires attached
to each terminal
 Context Help
Wires: data type is displayed
Features:
Lock Context Help
Hide/Show Optional Terminals and Full Path
Detailed Help
 LabVIEW Help
The LabVIEW Help utility contains detailed
descriptions of most palettes, menus, tools,
VIs, functions and instructions for using
LabVIEW features.
Bring up:
Help menu
Context Help window (Detailed help)
Example: Read From Spreadsheet File VI
 NI Example Finder
Help menu Find Examples
Example: Write to Text File VI
Browse Tab: pre-written examples
Search Tab: examples which match our search
 Quiz
Which of these can be used to help create
LabVIEW code?
a) Context Help
b) LabVIEW Help
c) NI Example Finder
d) All of the above
 Quiz
Which of the following is not a way to bring up
the Context Help window?
a) Press <Ctrl-H>
b) Right click a blank area on the Block Diagram
and select Context Help
c) Select Show Context Help from the Help
menu
 Quiz
What is displayed in the Context Help window
when you hover over a wire?
a) Its value
b) Nothing
c) Its data type
d) The function it connects to
 Quiz
Where can you find detailed descriptions of
most palettes, menus, tools, VIs and
functions?
a) Context Help
b) LabVIEW Help
c) NI Example Finder
d) None of the above
 Exercise
Complete the exercise:
LV1M8_LabVIEW Help Utilities
provided inside the moodle course!

Use the NI Example Finder to find and open a VI,

use Context Help to identify inputs and outputs
of a VI, and use LabVIEW Help to see the
detailed explanation of a VI.
Basic Debugging Techniques

LabVIEW Core 1, Module 9

 Agenda
What is a broken VI?
Debugging broken VIs
Using Execution Highlighting and Single-
Stepping
Using Probes to Check Data Values
Using Breakpoints to Pause the Code
 What is a broken VI?
Demo:
Creating a broken VI
A broken VI is one which can not run because of a problem in the code.
We can tell when a VI contains errors because the Run button actually
appears to be broken.
Warnings will not prevent a VI from running.
Errors must be resolved before a VI can run.
Error list
View-Error List or clicking the broken Run-button
Click Show error to highlight the piece of code that is causing the problem
Common causes for broken VIs:
A broken wire with either unconnected ends or a mismatch of data type
A required block diagram terminal that is unwired
A subVI that is broken
 Debugging broken VIs
Use the Error List from View Menu
Show Warnings check-marked
Triple-click a wire to show its entire path using
the Position tool
Use context help to check default values of VIs
One Object might hide another object
 Using Execution Highlighting and
Single-Stepping
Execution can be suspended to edit controls
and indicators, the number of times the VI
runs, or to re-execute the VI.
Demo:
execution highlighting and single-step mode
Enter Single-Step Mode by clicking the Step-
into button
Step Into, Step Over, Step Out
Using Probes to Check Data Values
The probe tool is used to observe intermediate
data values
To read the data along the wire
Retain Wire Values button
To run the code and probe afterwards
Breakpoints to pause execution, so we can single-
step or insert probes
Demo:
Using probes, retain wire values to see the previous
value of the wire
 Using Breakpoints to Pause the Code
To pause the code at a pre-defined position
right-click the wire, Set breakpoint, or Breakpoint
tool
Demo:
Breakpoint
When a VI pauses at a breakpoint, LabVIEW
highlights the object which contains the break
point.
Click the pause button to un-pause the VI
 Quiz
When you receive a warning, your code will
not run.
a) True
b) False
 Quiz
Which of the following will find the cause of
broken VIs?
a) Encountered warnings
b) Error list
c) Context Help Menu
d) Both a and b
e) Both b and c
 Quiz
Which of the following would not cause a
broken VI?
a) Different data types wired into the same
function
b) A broken wire with unconnected ends
c) A broken subVI
d) Unwired required block diagram terminal
 Quiz
What tool is used to triple-click a wire and
highlight its entire path?
a) Text tool
b) Wiring tool
c) Position tool
d) Scroll Tool
 Quiz
What values do Vis and functions pass if
optional inputs are unwired?
a) Zero
b) One
c) The default value
d) No value is passed
 Exercise
Complete the exercise:
LV1M9_Basic Debugging
provided inside the moodle course!

Use probes, breakpoints, execution highlighting,

and single-stepping to debug code.
 Undefined Data and Error
Handling: Tracking Errors in Code
LabVIEW Core 1, Module 10
 Agenda
What is undefined numerical data?
Tracking errors in code using error checking
and error handling
Reporting errors that occur in the code with
automatic and manual error handling
What is undefined numerical data?
Two types of undefined numerical data:
NaN Not a number
E.g. Square root of a negative number
Inf Infinity
Inf converted to an Integer generates a normal value
Use the Not a Number/Path/Refnum function
to check if a number is NaN
Compare to positive and negative Infinity
 Tracking errors in code using error
checking and error handling
An error is an output from a function or VI that indicated that it did
not execute as expected.
Error checking tells where and why an error occurs and how to
respond to it.
Error cluster data structure is a grouping of three different pieces of
data:
Status Boolean; True if an error occurs
Code 32 bit signed int; identifies the error, if everything is fine the
code will be 0
Source string; gives some explanation of the error
Error handling follows the dataflow model
Error cluster controls and indicators should
be used within subVIs
Explain error dialog box
 Reporting errors that occur in the code
with automatic and manual error handling
By default a VI or subVI uses automatic error handling
LabVIEW will suspend execution if an error occurs;
highlight the portion of code where the error occurred,
and display the error dialog box.
Can be disabled in the VI properties, execution cat.
Demo
Manual error handling makes use of the error-in and
error-out terminals
To enable it, we just need to wire the error-out and error-
in terminals
Use the LabVIEW error handling VIs and functions to
inform the user
Dialog and User Interface palette, Simple Error Handler VI
 Quiz
What does NaN stand for?
a) Numeric Access Node
b) Not a Number
c) Numeric and Null
d) Null Access Node
 Quiz
Which of these data types is undefined?
a) Int
b) DBL
c) Inf
d) Boolean
 Quiz
What value would be obtained if infinity was
converted to a 16-bit integer?
a) 65535
b) 32767
c) Undefined
d) 18
 Quiz
What are the tree pieces of data in an error
cluster?
a) Boolean Status, Integer Code, String Source
b) Boolean Status, Double, String Status
c) String Status, Integer Status, Double Status
d) Double Status, Code, Boolean Status
 Quiz
How would you view a detailed description of
an error?
a) Explain Error Dialog Box
b) Error Detail Dialog Box
c) Context Help
d) Detailed Help
 Exercise
Complete the exercise:
LV1M10_Undefined Data and Error Handling
provided inside the moodle course!

Build a VI to demonstrate how NaN numerics

can cause an error and how we can identify an
error that has occurred.
Front Panel Design: Customizing
the Front Panel
LabVIEW Core 1, Module 11
 Agenda
What is front panel design?
Designing controls and indicators
Organizing the front panel using color, space
and alignment, text and fonts
User interface tips and tools
 What is Front Panel design?
Inputs come from:
Acquiring from a device
Reading from a file
Manipulating controls
Outputs can be used to:
Display with indicators
Log to a file
Output to a device
 Designing controls and indicators
Demo
Choose appropriate controls and indicators
e.g. dial control for frequency,
thermometer indicator for
temperature
Label them clearly,
for longer descriptions use captions
Setting the default value for control
Right-click, Data operations, Make Current Value
Default
 Organizing the front panel using color,
space and alignment, text and fonts
Proper use of color
Avoid using too many colors!
Begin with a gray scheme
Use highlight colors for important
objects (plots, abort buttons, )
Small objects need brighter colors and more
contrast than larger objects
Use differences in contrast more often than
differences in color
Color-blind users!
 Organizing the front panel using color,
space and alignment, text and fonts
Spacing and alignment
the eye generally looks left to right and top to bottom
Align objects on the same line (horizontally and vertically)
Do not place objects too closely together
Fonts
Use matching fonts and only a few different font sizes
Font, Style, Size, Color
UIs for industrial applications
or touch screens often need
much larger fonts, more contrast,
larger controls and indicators.
 User interface tips and tools

Demo
Build in tools like system controls, tab controls,
decorations, menus and automatic resizing.
Display a dialog to interact with the user.
a VI can behave like a dialog box
VI properties, Windows Appearance, Dialog
Tab control overlap multiple pages
Use Decorations to group or separate objects
Automatic Resizing
VI properties, Window Size, Maintain prop, Scale all Obj
 Quiz
A control is also known as:
a) An interactive input
b) An interactive output
c) A Data Type
d) None of the above
 Quiz
An indicator is also known as:
a) An interactive input
b) An interactive output
c) A Data Type
d) None of the above
 Quiz
What type of control would be most
appropriate for controlling the frequency of a
sine wave?
a) Switch
b) Dial
c) Button
d) Tank
 Quiz
What type of indicator would be most
appropriate for displaying a temperature?
a) Vertical Progress Bar
b) Numerical Indicator
c) Thermometer
d) Gauge
 Quiz
Difference in color is typically better than
difference in contrast.
a) True
b) False
 Exercise
Complete the exercise:
LV1M11_Front Panel Design
provided inside the moodle course!

Use front panel labels, captions, color schemes,

and tab controls to organize a front panel.
Understanding and Using Data
Types
LabVIEW Core 1, Module 12
 Agenda
What are data types?
Using numeric data types
Using enums to limit selections to a defined
list
 What are data types?
The data type is represented by the color of
the terminal and the wire
E.g. Blue is an integer
Orange is an floating-point number
The representation can be changed
 Using numeric data types
Floating-point
Double-precision numbers (DBL) follow the 64-bit IEEE format
Single precision numbers need less memory
For values like amplitude we use floating-point numbers
Integer
Word length, number of bits used to store the number
Integers are represented with the color blue
Signed and unsigned integer
For counting we usually use integer, because we cannot count 4 and a
half times.
Demo: underflow with U8, 6-8=?
When using different data types, functions always return the larger
data type
Coercion dot
 Using enums to limit selections to a
defined list
The term enum is short for enumerated.
This data type can be used as a control, constant,
or indicator.
It assigns a numeric value to each entry in a series
of items.
Demo
Ring & Enum palette, Enum
Right-click and Edit items
Add days of the week
 Quiz
What color wire represents an integer data
type?
a) Orange
b) Blue
c) Yellow
d) Green
 Quiz
What color wire represents a decimal or
floating-point data type?
a) Orange
b) Blue
c) Yellow
d) Green
 Quiz
Unsigned integers include negative numbers.
a) True
b) False
 Quiz
What happens when two different numeric
representations are wired to an Add function?
a) A coercion dot appears on the larger
representation
b) A coercion dot appears on the smaller
representation
c) LabVIEW returns an error
d) LabVIEW returns a warning
 Quiz
Can an enum be used as which of the
following?
a) Control
b) Constant
c) Indicator
d) All of the above
 Exercise
Complete the exercise:
LV1M12_Understanding and Using Data Types
provided inside the moodle course!

Implement a simple application using different

numeric data types, representations and enums.
More LabVIEW Data Types

LabVIEW Core 1, Module 13

 Agenda
What are Data Types?
What is a Boolean?
What are Strings?
What is dynamic data?
 What are Data Types?
Data types describe the type of representation
of data.
They have corresponding controls and
indicators.
What is a Boolean and how is it used?
A Boolean is a data type whose value is
limited to two states (True and False).
LabVIEW stores Booleans as 8-bit values,
where a value of zero is false and any non-zero
value is true.
Demo: Boolean category of the Controls
palette
Mechanical Action: Properties Operation
 What is a String and how is it used?
A sequence of displayable or non-displayable
ASCII characters
A platform-independent format for
information and data
Common applications of strings include:
Creating simple text messages
Sending text commands to instruments
Storing numeric data to an ASCII file
 What is a String and how is it used?
Demo: String & Path category and the List,
Table & Tree category of the Controls palette
Right-click and select display mode
Manipulating strings: String category of the
Functions palette
What is Dynamic Data and when is it used?

Dynamic data stores the information

generated or acquired by an Express VI.
Dark blue terminal with dark blue wires
It can be wired to any indicator or input that
accepts numeric, waveform, or Boolean data.
For other data types: Convert from Dynamic
Data Express VI
 Quiz
How many states can a Boolean have?
a) 1
b) 2
c) 3
d) Infinite
 Quiz
How many bits of memory are required to
store a single element of Boolean data?
a) 1
b) 8
c) 16
d) 32
 Quiz
Which of the following is an option for a
Booleans mechanical action?
a) Switch When Pressed
b) Switch Until Released
c) Latch When Released
d) All of the above
 Quiz
What color wire represents a Boolean data
type?
a) Orange
b) Blue
c) Yellow
d) Green
 Quiz
Which of the following is not a possible
display mode for a string?
a) Normal Display
b) Password Display
c) Numeric Display
d) \ Codes Display
 Exercise
Complete the exercise:
LV1M13_More LabVIEW Data Types
provided inside the moodle course!

Use the Boolean and string data types to create

a basic login interface.
Documenting Code

LabVIEW Core 1, Module 14

 Agenda
Why is Documentation important?
Using tip strips and descriptions to convey
information to the user
Using VI Properties to convey VI information
Using block diagram documentation
Why is documentation important?
Documenting the block diagram is important
for maintainability and scalability of every
LabVIEW VI.
Documenting the front panel is important for
explaining proper use of the VI to the user.
 Using Tip Strips and Descriptions
Tip strips are brief descriptions that show up
when hovering over an object on the front
panel.
Demo: Create numeric control and enter tip.
Descriptions provide additional information
about controls and indicators that appear in
the Context Help window.
Demo: Enter Description and open Context
Help window.
 Using VI Properties
A very useful tool to convey information when
using subVIs is the Documentation tab of the
VI Properties.
Demo: right-click the VI icon and select VI
Properties, Documentation in the Category
dropdown
VI description contains the text that appears
in the Context Help window when the cursor
is placed over the VI icon.
 Using VI Properties
The Help tag contains the HTML filename or
index keyword of the topic to be linked to in a
compiled help file.
The help path contains the path of the HTML
or compiled help file to be linked.
More information can be found by pressing
the Help button.
 Using Block Diagram Documentation
Block diagram labels:
Labels on VIs or functions,
Labels on wires, or
Free labels.
Demo: create all three types of labels
 Quiz
Documenting code makes it easier to track
down errors.
a) True
b) False
 Quiz
What shows up after hovering over an object
on the front panel?
a) Description
b) Label
c) Caption
d) Tip Strip
 Quiz
What shows up in the Context Help menu
when hovering over a subVI?
a) Description
b) Label
c) Caption
d) Tip Strip
 Quiz
Which is an example of a block diagram label?
a) VI Label
b) Function Label
c) Free Labels
d) All of the above
 Quiz
Documenting code is important for
maitainability and scalability of code.
a) True
b) False
 Exercise
Complete the exercise:
LV1M14_Documenting Code
provided inside the moodle course!

Use tip strips and descriptions for controls and

indicators, use VI Properties to document a VI,
and add block diagram labels to fully document
code.
 While Loops:
Repeating the Code
LabVIEW Core 1, Module 15
 Agenda
What is a While Loop?
Using While Loops to repeat code
Managing the loop with iteration and
conditional terminals
Transferring data into and out of a loop:
tunnels
Ensuring smooth execution of the code: error
checking and handling
 What is a While Loop?
A While Loop is a structure that continuously
executes its containing code while or until a
condition is met.
Similar to a Do While or Do Until loop in text-
based programming
 What is a While Loop?

The code contained within the loop will

execute, the condition will be checked, and
the loop will then repeat or end, based of the
evaluation of the condition.
 What is a While Loop?
When using a While Loop, it is important to
note that the code will always execute at least
once.
Using While Loops to Repeat Code
Demo: create a While Loop that will iterate
until a random number generator creates a
value above 0.5.
Preserving the code in the loop: right-click on
the loop border Remove While Loop.
Methods for moving code inside the loop:
Draw the While Loop around
Drag the code inside
Managing the Loop with Iteration and
Conditional Terminals
The iteration terminal is an output terminal
that outputs the number of previously-
completed iterations (starting at 0).
The conditional terminal is an input terminal
that receives a Boolean value. It has two
different behaviors:
Stop if true
Continue if true (change with left- or right-click)
Run the While Loop (Execution Highlighting)
 Transferring Data
Tunnels route data into and out of structures.
The tunnel generally appears as a solid block
on the border of the While Loop.
Move the numeric constant outside the loop
and wire it.
When data is routing out of the loop, the data
will only be passed out of the loop when the
loop finishes executing.
 Transferring Data
Demo: Duplicate the While Loop and wire the
Boolean of the first loop to the second loop.
Run the While Loop (Execution Highlighting)
 Error Checking and Handling
Ensuring smooth execution of the code: wire
an Error Cluster directly into the conditional
terminal.
Demo: While Loop with Simulate Signal
Express VI, wire Error Out to Conditional
Terminal
Demonstrate error: frequency value = 501
 Quiz
Which data type is accepted into the condition
terminal of a While Loop?
a) Double
b) Integer
c) Boolean
d) String
e) All of the above
 Quiz
Which terminal does not exist in a While
Loop?
a) Loop Condition
b) Loop Count
c) Loop Iteration
 Quiz
A While Loop can run zero times.
a) True
b) False
 Quiz
In which situation would you typically use a
While Loop?
a) When you want to acquire 10 points of data
b) When you want to acquire data until a condition
occurs
c) When you want to perform different actions in
different situations
d) None of the above
 Quiz
What is the value of the iteration terminal on
the fifth iteration of a While Loop?
a) 4
b) 5
c) 6
d) None of the above
 Exercise
Complete the exercise:
LV1M15_While Loops
provided inside the moodle course!

Create and use a While Loop to calculate how

many iterations it will take to match a randomly
generated number to a defined number.
 For Loops:
Running Code a Predetermined
Number of Times
LabVIEW Core 1, Module 16
 Agenda
What is a For Loop and how do we use it?
What are the terminals on a For Loop?
Using numeric conversion when defining the
number of iterations.
 What is a For Loop?
A For Loop adds the ability to run code a
predetermined number of times.
Useful in situations when we are acquiring or
analyzing data sets of known lengths.
 What is a For Loop?
Demo: create a For Loop
Replace While Loop with For Loop (right-click)
What are the Terminals in a For Loop?
Iteration Terminal: behaves the same way on a
For Loop as it does on a While Loop
Count Terminal: input, that is used to
determine how many times to iterate (must
be wired)
Demo: show function of the terminals
A For Loop can execute zero times!
What are the Terminals on a For Loop?
Conditional Terminal: has to be added by
right-clicking the border it behaves exactly
the same as in a While Loop.
In a For Loop, the loop will stop running when
it has reached its defined count even if the
condition hasnt been met.
Demo: stop For Loop when iteration count = 2
 Using Numeric Conversion When
Defining the Number of Iterations
The number of iterations must be specified in
non-negative integers.
Demo: wire a double-precision floating-point
numeric to the count terminal LabVIEW
converts to 32-bit signed integer
 Quiz
Which data type is used by the count
terminal?
a) String
b) Boolean
c) Integer
d) Double
 Quiz
A For Loop can run zero times.
a) True
b) False
 Quiz
In which situation would you typically use a
For Loop?
a) When you want to acquire 10 points of data
b) When you want to acquire data until a condition
occurs
c) When you want to perform different actions in
different situations
d) None of the above
 Quiz
It is possible to stop a For Loop before the
requested number of iterations is complete.
a) True
b) False
 Quiz
What happens when a double numeric
constant is wired into the count terminal?
a) A fraction of the loop will run based on the
decimal part of the value
b) An error occurs
c) The loop will run indefinitely
d) The value will be coerced into a 32-bit integer
 Exercise
Complete the exercise:
LV1M16_For Loops
provided inside the moodle course!

Create and use For Loops and compare them to

While Loops.
Timing Functions, Iterative Data
Transfer and Shift Registers:
Controlling the Timing of a Loop
LabVIEW Core 1, Module 17
 Agenda
Why use timing functions?
How do we use timing functions?
What is iterative data transfer?
Using shift registers.
 Why use timing functions?
Free running loops consume all the
performance of the CPU.
Demo: Free running while loop, loop count
indicator, observe the task manager
By using timing functions we can control the
frequency at which a loop executes.
e.g. acquiring data every two seconds
 How do we use timing functions?
Demo: Timing palette, Wait function (100ms),
observe the task manager
Wait until Next ms Multiple function
Useful for synchronizing activities across loops or
for setting a sampling rate
Tick count function
 What is iterative data trasfer?
A shift-register allows data to flow between loop
iterations.
Demo: right-clicking the border of the loop, Add
Shift Register, initialize by wireing a value into the
left side, (remove afterwards the init)
The value which comes out on the left side after the
first iteration will be the value which was stored on
the right side on the previous iteration.
If we want to remember values of multiple
previous iterations, we can create stacked shift
registers.
 Using shift registers
Demo: calculate the time between the
iterations of a loop.
Tick Count function
Uninitialized shift registers return a default
value of zero (if the loop has never run) or the
value of the last iteration.
 Quiz
Which is the preferred method to pass data
between loop iterations?
a) Tunnels
b) Shift registers
c) Indicators
d) Controls
 Quiz
An uninitialized shift register will cause a
broken Run button
a) True
b) False
 Quiz
Which data type can be used in a shift
register?
a) Integer
b) Double
c) Boolean
d) All of the above
e) None of the above
 Quiz
You can use shift registers to access data from
previous iterations
a) True
b) False
 Quiz
You can use more than one shift register in a
loop
a) True
b) False
 Exercise
Complete the exercise:
LV1M17_Timing Functions
provided inside the moodle course!

Use the Tick Count and Wait timing functions

and use shift registers on while loops to store
data between iterations.
Case Structures: Allowing Our
Program to Make Decisions
LabVIEW Core 1, Module 18
 Agenda
What is a case structure?
Selecting a case.
Using case structures with different data
types.
Transferring data into and out of case
structures with input and output tunnels.
 What is a case structure?
If the code needs to decide which action to take
next, we need to use a case structure.
has two or more subdiagrams or cases
case selector chooses which case to execute

Demo: place case structure from structures

palette into the while loop
 Selecting a case
Demo
The selector terminal can be wired with
Boolean values, strings, numerics, enums and
error cluster values.
The case selector lable contains the name of
the current case.
Right-click to Add case..., Duplicate case, Delete
case
 Transferring data into and out of case
structures with input and output tunnels
Demo:
Increment/Decrement switch,
wire the initialized shift register into the case
structure,
TRUE: increment function,
FALSE: decrement function,
wire output to numeric indicator
Use default if unwired
not a good programming practice
 Using case structures with different
data types
Demo:
Numeric control Dec (0), Inc (1), Reset (2), U8
wired into the case selector
Add a new case: reset case 2, wire 0 to the output
tunnel, Make this case default
Demo:
Create an enum (Inc, Dec, Reset)
connect it to the case selector
 Quiz
A case structure can be used to
programmatically choose an action.
a) True
b) False
 Quiz
A case structure will always run code multiple
times.
a) True
b) False
 Quiz
Which data type can be wired into the
selector terminal of a case structure?
a) Boolean
b) Numeric
c) String
d) All of the above
e) None of the above
 Quiz
Which data type can be used to make case
names more descriptive?
a) Boolean
b) Numeric
c) Enum
d) None of the above
 Quiz
Use Default if Unwired is a property which can
be applied to which of the following?
a) Output tunnel
b) Shift register
c) Input tunnel
d) Case selector
e) None of the above
 Exercise
Complete the exercise:
LV1M18_Case Structures
provided inside the moodle course!

Use case structures to perform different actions

based on the values of controls.
Wiring and Debugging
Techniques
LabVIEW Core 1, Module 19
 Agenda
Wiring techniques
Debugging techniqes
 Wiring techniques
Left to right: enforced by LabVIEW
Avoid crossing of wires whenever possible
Avoid unneccessary wire kinks
Press the space-bar to change the orientation of
the wiring path
Minimize the size of the block diagram to the
size of one screen
Place repeated code or sprawling code inside
subVIs
If scrolling, than scroll only in one direction
 Debugging techniques
Error list window
to highlight the error on the block diagram
Probes on certain wires to check values
Execution highlighting to watch the code run
Breakpoints to pause the code
Single-stepping once the breakpoint is reached
 Quiz
On a block diagram, in which direction should
code be written or read?
a) Right to left
b) Top to bottom
c) Left to right
d) Bottom to top
 Quiz
How do you select all branches of a wire?
a) Single-click
b) Double-click
c) Triple-click
d) Control-click
 Quiz
While creating a wire, how can we change the
orientation of the wire?
a) Press the spacebar while wiring
b) Double-click while wiring
c) Right-click while wiring
d) Hold <Ctrl-O> while wiring
 Quiz
Which debugging tool is associated with a
broken Run button?
a) Probes
b) Error List Window
c) Execution highlighting
d) Single stepping
 Quiz
Execution highlighting slows down the
execution of code.
a) True
b) False
 Exercise
Complete the exercise:
LV1M19_Wiring and Debugging Techniques
provided inside the moodle course!

Clean up a block diagram and use probes, single-

stepping, and breakpoints to debug code.
Arrays: Grouping Data

LabVIEW Core 1, Module 20

 Agenda
What is an array?
How can we create and use arrays?
Auto-indexing array inputs and outputs.
Using arrays with loops.
 What is an array?
Data structure that:
Consists of elements
Has one or more dimensions
Is used to group data of the same data type
How do we create and use arrays?
Demo:
Add array shell to the front panel, place a data object
into the shell, enlarge the array to 5 elements and set
them
The index value indicates the position of the
element inside the array
Zero-indexed (like loops)
We can not create an array within another array
we can increase the dimension
2D-array is like a spreadsheet, rows and columns
Right-click index display, add dimension
How do we create and use arrays?
Demo:
To create an array constant, add an array shell to
the block diagram, place a constant into the shell,
...
the rest is similar to an array shell on the front
panel
 Auto-indexing Array Inputs and Outputs

Arrays store data produced in a loop, each

iteration produces one element.
Auto-indexing is used to link each iteration of the
loop to an element from the array.
Demo:
Modify the case example; use a for loop, run it 500
times, wire the counter output to the edge of the for
loop, create an indicator outside the loop
Auto-indexing is turned on by default in the case
of for-loops
 Auto-indexing Array Inputs and Outputs

Nested loops will

generate multi-
dimensional arrays
Auto-indexing allows us to
leave the count terminal
unwired
The count information is
derived from the array size
 Quiz
Arrays can be used to group items with
different data types.
a) True
b) False
 Quiz
Wires in the block diagram for arrays are the
same color as the corresponding scalar
a) True
b) False
 Quiz
Which of the following data types can be used
to create an array?
a) Boolean
b) String
c) Numeric
d) All of the above
e) None of the above
 Quiz
Arrays are a good tool for storing data
produced by a loop.
a) True
b) False
 Quiz
Arrays con contain more than one dimension
a) True
b) False
 Exercise
Complete the exercise:
LV1M20_Arrays
provided inside the moodle course!

Manipulate arrays using the auto-indexing

feature of For Loops.
 Array Functions:
Manipulating Arrays
LabVIEW Core 1, Module 21
 Agenda
Introduction
Creating and manipulating arrays
Exploring other array functions in LabVIEW
 Creating and Manipulating Arrays
Is there a way to create and manipulate an array
without using loops?
Demo: Small business wants to track the vacation days
of its employees
Initialize Array function; Size: 5; Element: 10, Indicator to
display output
Arrays are great tools for storing multiple pieces of
data of the same data type
Demo: modify an element
Index Array function, Index 1, Decrement Function
Replace Array Subset function, Index Value: 1, Create
Indicator
 Creating and Manipulating Arrays
Demo: Adding Elements to the array
Insert Into Array function, Index 2, New Value: 8,
Create Indicator
Because arrays are zero indexed, the value for
the position will be one less than the order of
the element.
Another method to add an entry to the end of
the array:
Build Array function (concatenating inputs)
 Creating and Manipulating Arrays
Demo: Tracking vacation days and sick days at
the same time
Form a two-dimensional array using the Build
Array function (concatenate inputs turned OFF!)
Index Array function (note: expanding), Column
Index 2
 Exploring Other Array
Functions in LabVIEW
Delete From Array will delete a subset of an
array defined by index and length.
Search 1D Array will search an array for a
defined element, and return the index of the
first instance of that element that is found.
 Quiz
Which function can we use to create an array?
a) Initialize
b) Build
c) Index
d) Replace
e) Both a) and b)
 Quiz
Which function can output an array with a
higher dimension than the input?
a) Initialize
b) Build
c) Index
d) Replace
e) Both a) and b)
 Quiz
Which function can output an array with a
smaller dimension than the input?
a) Initialize
b) Build
c) Index
d) Replace
e) Both b) and c)
 Quiz
Which function can output an array with the
same dimension as the input?
a) Initialize
b) Build
c) Index
d) Replace
e) Both b) and d)
 Quiz
The Insert Into Array function can only be
used to add a single element to an array.
a) True
b) False
 Exercise
Complete the exercise:
LV1M21_Array Functions
provided inside the moodle course!

Use functions in the Array sub-palette to

manipulate arrays.
Clusters: Grouping Data

LabVIEW Core 1, Module 22

 Agenda
Introduction
What is a cluster?
How do we create and use clusters?
 What is a Cluster?
Arrays group together data elements of the
same type.
Clusters group together data elements of
mixed types.
An error cluster is an example.
Similar to a record or a struct in text-based
programming languages
 What is a Cluster?
Elements that make up a cluster must be
added individually.
It is either a control or an indicator, and
cannot contain a mixture of controls and
indicators.
 What is a Cluster?
We often pass many pieces of data between
structures or subVIs.
We can use clusters to pass the data more
easily and with less clutter.
The connector pane has 28 terminals at most,
therefore we can use a cluster to pass more
data.
 How do we create and use Clusters?
Demo: create a cluster
Place cluster shell (Array, Matrix, & Cluster
palette)
Drag data objects or elements into the cluster
shell (enum -> rename to Command)
Add three numerics and call them Counter, Max,
and Min (integers)
Arrange: AutoSizing and options
Cluster order: maybe different from order in block
diagram -> re-order!
 How do we create and use Clusters?
Demo: using Bundle and Unbundle functions
Wire cluster into shift register of an For loop
Drop Unbundle by Name function (compare to
Unbundle function)
To replace the values of one or more elements in a
cluster -> Bundle by Name function (wire cluster
to the middle terminal)
Wire output into right terminal of the shift register
How do we create and use Clusters?
 Quiz
Clusters can be used to group items with
different data types.
a) True
b) False
 Quiz
Clusters can be used as which type of object?
a) Controls
b) Indicators
c) Constant
d) All of the above
 Quiz
The Unbundle function will always unbundle
all elements of the cluster.
a) True
b) False
 Quiz
The Unbundle by Name function will always
unbundle all elements of the cluster.
a) True
b) False
 Quiz
Clusters must always have a fixed size.
a) True
b) False
 Exercise
Complete the exercise:
LV1M22_Clusters
provided inside the moodle course!

Create clusters on the front panel window,

reorder clusters, and use the cluster functions to
assemble and disassemble clusters.
Plotting Data: Graphs and Charts

LabVIEW Core 1, Module 23

 Agenda
Introduction
How to plot data
What are waveform charts?
What are waveform graphs?
What are XY graphs?
How to Plot Data
 What are Waveform Charts?

A waveform chart is a special type of numeric

indicator that displays one or more plots of
data, typically acquired at a constant rate.
 What are Waveform Charts?
A chart is used to update data as it is acquired.
It is also an effective way to display data with
history.
A waveform chart can have one of three updates
modes: Strip Chart, Scope Chart, and Sweep
Chart.
Demo: Waveform chart; change modes
To wire multiple plots on the waveform chart, we
use a cluster of numerics.
Demo: change plot legend, scale legend
 What are Waveform Graphs?
Waveform graphs are used to plot single-value
functions, with evenly-distributed points along
the x-axis.
These graphs can also have single or multiple
plots.
Data for a waveform graph is usually collected
in an array.
Demo: Waveform graph
 What are Waveform Graphs?
Waveform graphs are different from charts in that
they dont display data being added point by
point.
Notice that the x-axis is labelled as Time, but
what is actually being used is the index of the
element in the array.
We can also use a waveform data type to plot
data on the graph, which allows us to define a
starting time and a time between points.
Demo: Build Waveform function
What are Waveform Graphs?
 What are XY Graphs?
Both of the waveform chart and waveform
graph that we just examined assume that the
data that is distributed evenly along the x-axis.
When this is not the case, we can use an XY
graph to associate specific X values with our
data points.
The spacing of data is non-uniform, and XY
graphs can also have single or multiple plots.
 What are XY Graphs?
Demo: XY Graph
 Quiz
Which type of graph keeps a history of
previously plotted data?
a) Waveform Chart
b) Waveform Graph
c) XY Graph
d) All of the above
e) None of the above
 Quiz
Which type of graph would we use to display
an evenly distributed function?
a) Waveform Chart
b) Waveform Graph
c) XY Graph
d) All of the above
e) None of the above
 Quiz
Which type of graph would we use to display
data points associated with non-evenly
distributed points in time?
a) Waveform Chart
b) Waveform Graph
c) XY Graph
d) All of the above
e) None of the above
 Quiz
Which type of graph is capable of displaying
multiple plots?
a) Waveform Chart
b) Waveform Graph
c) XY Graph
d) All of the above
e) None of the above
 Quiz
Which function is used to define the start time
and increment for a waveform?
a) Build Waveform
b) Unbundle
c) Build Array
d) All of the above
 Exercise
Complete the exercise:
LV1M23_Plotting Data
provided inside the moodle course!

Plot multiple data sets on a single waveform

chart and customize the chart.
Type Definition: Custom Controls

LabVIEW Core 1, Module 24

 Agenda
Introduction
What is a Type Definition?
How do we create Type Definitions?
Customizing the appearance of controls
 What is a Type Definition?
It is important to modularize code into subVIs,
so that it is easy to modify, scale, and to
debug.
Clusters can be used to simplify the usage of
multiple pieces of data.
Type definitions can be used to define and
save data types.
 What is a Type Definition?
Type of customized control used to define a
customized data type.
Can be used in multiple instances across a
project.
Saved as a .ctl file
 What is a Type Definition?
By making a change to the type definition, we
can change all instances.
We can maintain one instance of the type
definition, acting like a single central location
for all instances.
Type definitions can be used as controls,
constants, and indicators.
 What is a Type Definition?
Type definitions will only maintain the data
type, not the appearance or specific data
inside the control, constant, or indicator.
To maintain the appearance of custom
controls, we can use strict type definitions.
 How do we create Type Definitions?
Demo: right-click control or indicator, select
Advanced, then Customize.
Use Type Definition Status pull-down to
choose between Type Def., Strict Type Def., or
Custom Control.
Start with Type Def., change it later to Strict
Type Def., Save
Extend Enum, Save and Update
 Customizing the Appearance of
Controls
Demo: customize the appearance of a
numeric control.
Select Window Show Parts
Import pictures
 Customizing the Appearance of
Controls
Demo: search for controls in the NI Example
Finder
Open the Using Custom Controls example
 Quiz
Type definitions act as a single central location
for our customized data types.
a) True
b) False
 Quiz
Type definitions can be used as which type of
object?
a) Controls
b) Indicators
c) Constants
d) All of the above
 Quiz
A Type Definition will maintain the
appearance of a control.
a) True
b) False
 Quiz
A Strict Type Definition will maintain the
appearance of a control.
a) True
b) False
 Quiz
Individual items of a control, such as the
increment button, cannot be customized.
a) True
b) False
 Exercise
Complete the exercise:
LV1M24_Type Definitions
provided inside the moodle course!

Create a type definition and a strict type

definition and identify the differences.
Understanding File I/O

LabVIEW Core 1, Module 25

 Agenda
What is file I/O?
What are the different file types?
How do we use high-level file I/O VIs?
 What is File I/O?
Create or Open the file
Unique ID - Refnum
Read from or Write to the file
Close the file
Error handling
 What are the different file types?
Binary File
Underlying file format of all other file formats
least amount of overhead, small and fast
ASCII File, Text File
Specific type of binary file that is a standard used by most
programs
LVM - LabVIEW measurement data
a tab-delimited text file you can open with a spreadsheet
application or a text-editing application
TDMS File
Type of binary file created for NI products consisting of
two separate files: a binary file and a binary index file
How do we use high-level file I/O VIs?
Perform all three steps (open
read/write, close) for common
file I/O operations.
Might not be as efficient as the
functions configured of
designed for individual
operations.
Low-Level File I/O VIs
Individual VI for each step
Used for writing to a file in a loop.
How do we use high-level file I/O VIs?
Demo
place a Write to Spreadsheet File VI outside the For
loop
wire the Min and Max Values to the edge of the For
loop and Build Array with Counter, Min and Max
look into the context help of the File VI
Demo
New VI, Read from Spreadsheet File VI
Choose a constant for the path, right-click and browse
for path
Create a Waveform Graph and display the data
 Quiz
Which sequence of steps is required for file I/O?
a) Open, Authenticate, Read/Write, Close
b) Open, Read/Write, Close
c) Scan, Open, Transfer, Close
d) Open Analyze, Close
 Quiz
Binary file types are typically smaller than text
files containing the same data
a) True
b) False
 Quiz
Which file type is not used in LabVIEW?
a) Text File
b) LabVIEW Measurement Data File
c) TDMS File
d) Universal Transfer File
 Quiz
High-level VIs allow more control and
flexibility than low-level VIs when performing
I/O.
a) True
b) False
 Quiz
What happens when a specified path to read
from in invalid
a) An error occurs
b) The path will default to the C: directory
c) The VI will skip the function
 Exercise
Complete the exercise:
LV1M25_Understanding File IO
provided inside the moodle course!

Use a high-level file I/O VI to write to a

spreadsheet-readable file.
Understanding Low-Level File I/O

LabVIEW Core 1, Module 26

 Agenda
What is low-level file I/O?
Disk streaming
 High-Level File I/O VIs
High-level file I/O VIs make programming simple, by
wrapping up all of the steps of the I/O process:
Opening a file
Writing to a file
Reading from a file
Closing the file
 What if Low-Level file I/O?
Low-level file I/O VIs and functions perform
one piece of the file I/O process and are faster
and more efficient than high-level ones.
Low-level file I/O includes functions to open,
read, write, and close files.
 Disk Streaming
Disk streaming is a technique for keeping files open while we perform
multiple write operations within a loop.
Demo:
Place an Open/Create/Replace File function to the left of the For loop and a
Close file function to the right of the For loop.
Place a Write to Text File function inside our loop.
Wire it together, replace the refnum and error tunnel with shift registers
Operation: open or create
Place a Number to Decimal String function inside our loop (Counter Value)
Place a Concatenate String function with a Carriage return constant
Demo:
Blank VI, Open/Create/Replace File function, Close File function, and Read
from Text File function
Create a path constant, Browse for Path
Create a String indicator
 Quiz
Low-level file I/O VIs and functions perform
more than one piece of the file I/O process.
a) True
b) False
 Quiz
What is a technique for keeping file open
while multiple write operations are performed
within a loop?
a) Write Looping
b) Disk Streaming
c) Low-Level Looping
d) All of the Above
 Quiz
When continuously saving with low-level file
I/O functions, the file is opened before the
loop starts and closed once when the loop
finishes.
a) True
b) False
 Quiz
What is a character called which signifies a
separation between pieces of data in a
spreadsheet file?
a) Placeholder
b) Threshold
c) Separator
d) Delimiter
 Quiz
Low-level file I/O VIs are more efficient when
performing multiple write-operations
a) True
b) False
 Exercise
Complete the exercise:
LV1M26_Understanding Low Level File IO
provided inside the moodle course!

Modify a VI to create an ASCII file using disk

streaming.
DAQ: Acquiring Data

LabVIEW Core 1, Module 27

 Agenda
What is DAQ?
Using DAQ Software
Using the DAQ Assistant
 DAQ Programming
DAQ - Data Acquisition
1. Signal
2. Terminal Block
3. Cable
4. DAQ Device
5. Computer
 What is DAQ?
Use LabVIEW to interface and communicate
with the DAQ system.
Acquire data using the DAQ Assistant Express
VI.
Use LabVIEW to process, analyze, save, and
display data.
 Using DAQ Software
Demo:
Measurement and Automation Explorer - MAX
Devices and Interfaces
Create New: Simulated NI-DAQmx Device or
Instrument
X-Series, NI PICe 6351 Device
 NI-DAQmx
Driver-level software that can be installed
with LabVIEW
Set of VIs which can be used to program DAQ
applications
Configurable Express VI used to create a DAQ
application
 Using the DAQ Assistant
Demo:
Blank VI, Measurement I/O, NI-DAQmx, DAQ
Assistant
Acquire Signals, Analog Input, Voltage, a0-a3
Acquisition mode: Continuous, click Run-button to
try, OK
Create a Graph Indicator for the data
 Quiz
DAQ stand for Data Acquisition.
a) True
b) False
 Quiz
The first step to configure a DAQ program uses
which tool?
a) The DAQ API
b) The DAQ Assistant
c) MAX
d) None of the above
 Quiz
The Advanced Timing tab allows you to
choose from internal or external sample clock
sources.
a) True
b) False
 Quiz
Which data file type can be enabled to log
data using the DAQ Assistant?
a) LVM
b) TDMS
c) TDM
d) None of the Above
 Quiz
If you are acquiring data continuously you
should run the DAQ Assistant in a loop.
a) True
b) False
 Exercise
Complete the exercise:
LV1M27_Data Acquisition_DAQ
provided inside the moodle course!

Build a simple example with the DAQ Assistant.

 DAQ Programming

LabVIEW Core 1, Module 28

 Agenda
What is the DAQmx API?
Programming with DAQmx
 What is the DAQmx API?
The DAQmx API is a set of VIs which allows us to read
from and write to DAQ devices.
DAQmx API VIs takes advantage of the powerful and
flexible DAQ options available within LabVIEW.
 Programming with DAQmx
Processes of a DAQ Program
Creating a task
Configuring the task
Starting the task
Acquiring or generating data
Clearing the task
 Programming with DAQmx
Demo:
Example Finder, Search DAQmx,
Acq One Sample.vi,
Cont Acq&Chart Samples-Int.vi
Acq&Graph Voltage-Int.vi
Configure DAQ channels, ai0-ai3
Examine the block diagram
 Quiz
Which process is involved in a basic DAQ
program?
a) Creating a task
b) Starting a task
c) Acquiring and generating data
d) Clearing the task
e) All of the above
 Quiz
A polymorphic VI can have different forms.
a) True
b) False
 Quiz
What are the different forms of a Polymorphic
VI called?
a) Cases
b) Methods
c) Instances
d) Procedures
 Quiz
Which type of channel can be read with the
DAQmx Read VI?
a) Analog
b) Digital
c) Counter
d) All of the above
e) None of the above
 Quiz
Which VI is not part of the DAQmx API
a) DAQmx Read VI
b) DAQmx Clear Task VI
c) DAQmx Timing VI
d) All of the above
e) None of the above
 Exercise
Complete the exercise:
LV1M28_DAQ Programming
provided inside the moodle course!

Explore a DAQmx example program that

continuously acquires data, and modify it to
wait on a digital trigger.
Instrument Control

LabVIEW Core 1, Module 29

 Agenda
Introduction
What is instrument control?
Instrument control software?
What are instrument drivers?
Using instrument drivers
 What is Instrument Control?
Refers to the use of software to control an
instrument
Important application of LabVIEW
Uses instrument control buses to
communicate with devices
 Instrument Control
General Purpose Interface Bus (GPIB)
Serial
Ethernet
Universal Serial Bus (USB)
IEEE 1394 (FireWire)
 Instrument Control Software
Measurement & Automation Explorer (MAX)
MAX can be accessed from inside LabVIEW by
selecting Measurement & Automation
Explorer from the Tools menu.
Only in the Lab: select the Agilent 33521A
Function/Arbitrary Waveform Generator.
 What are Instrument Drivers?
Set of high-level functions
Controls and communicates with a
programmable instrument
Generally use the LabVIEW VISA application
programming interface (API)
 Instrument Driver VIs
Are not required to use the instruments
Simplify instrument control
Reduce test program development time
Eliminate the need to learn the complex low-
level programming commands
 Using Instrument Drivers
Demo: Open the Instrument Driver Finder by
selecting Instrumentation from the Tools menu
and then selecting Find Instrument Drivers.
Install the driver for our Agilent 33521A.
Find Examples: Frequency Sweep.
Examine the Block Diagram: The VIs in an
instrument driver are organized into six
categories. These categories are: Init, Config,
Action/Status, Data, Utility, and Close.
 Quiz
Instruments can only be connected to the
computer using the USB bus.
a) True
b) False
 Quiz
What is the purpose of the Measurement &
Automation Explorer?
a) It uses the VISA API functions to communicate
with a device
b) It downloads instrument drivers
c) It configures the hardware that is installed on
the computer
d) Both a) and b) are correct
 Quiz
Which of the following is not true about
instrument drivers?
a) They are required to use the instrument
b) Manufacturers sometimes provide instrument
driver VIs
c) They can be downloaded using the NI
Instrument Drivers Finder
d) They can simplify instrument control
 Quiz
Which of the following is not one of the
categories that the VIs in an instrument driver
are divided into?
a) Init
b) Config
c) Action/Status
d) Data
e) Reference
 Quiz
The instrument driver VIs make calls to low-
level device driver VIs.
a) True
b) False
 Exercise
Complete the exercise:
LV1M29_Instrument Control
provided inside the moodle course!

Use an instrument driver to communicate

effectively with an instrument.
Instrument Control Programming

LabVIEW Core 1, Module 30

 Agenda
Introduction
Using the Instrument I/O Assistant
What is the VISA API?
VISA programming
Using the Instrument I/O Assistant
Some of the commands will be common
among many devices, like the identify
command.
These common commands are defined by the
Standard Commands for Programmable
Instruments, or SCPI, standard.
The Instrument I/O Assistant is a great tool for
quickly interfacing with a device.
Using the Instrument I/O Assistant
Demo: open Express VI Instrument I/O
Assistant
This Express VI is similar to the DAQ Assistant,
but communicates with a VISA device instead
of a DAQ device.
To add a step, we can click Add Step at the top
of the screen -> add one of each step
Using the Instrument I/O Assistant
Demo: enter *IDN? in the Query and Parse
(Abfragen und Analysieren) step this is the
identify command.
Click the Auto Parse (Autom. Analyse) button.
Click the To End of Data (Nach Ende der
Daten) button.
Rename the tokens and return to LabVIEW,
wire a string indicator.
 What is the VISA Application
Programming Interface (API)?
LabVIEW includes device drivers to
communicate with instrumentation.
VISA functions allow you to send specific
commands to the instrument.
 VISA API
High-level API
Calls low-level drivers
Uses the same functions to communicate with
different instruments
Uses the same functions to interact with a
large number of communication protocols
 VISA Terminology
Resource any instrument in the system
Instrument descriptor the exact name of a
resource
Session connection
VISA Alias a user-defined name
 VISA Programming
VISA functions operate similar to File I/O
functions.
First, we open a session with a VISA resource,
i.e. the instrument.
Then we perform I/O operations.
Finally, we close the session to the VISA
resource.
 VISA Programming
Demo: search for GPIB in the NI Example Finder
Open GPIB-VISA.vi; delete step no. 2
VISA Open establishes a communication line to
resource.
We use the VISA Write function to send a
command or query string to an instrument
(*IDN?)
We use the VISA Read function to read a
response from the instrument.
VISA Close will close the session.
 Quiz
Which of the following is a benefit of using the
VISA functions?
a) VISA functions provide interface independence
b) VISA functions allow faster connection between
hardware and computer
c) VISA functions convert codes for other serial
devices
d) VISA functions install the drivers for the
hardware
 Quiz
Which of the following is not a step inside the
instrument I/O Assistant?
a) Write
b) Query and Parse
c) Read and Parse
d) Timeout
 Quiz
Which of the following is true about the
Instrument I/O Assistant Express VI?
a) The Query and Parse step can only read and
parse the data
b) It is located in the Structures Palette
c) The Write step reads the data from the device
d) It communicates with a VISA Instrument
 Quiz
What is the Auto Parse button used for?
a) It automatically converts raw data received from
the instrument into a usable data type
b) It automatically receives raw data from the
instrument
c) It automatically converts usable data into raw
data to send to the instrument
d) It automatically writes the command to the
instrument
 Quiz
Which of the following is not part of the
typical VISA program flow?
a) Writing string commands
b) Closing a session
c) Connecting the instrument to the computer
d) Reading the response strings
e) Opening a session
 Exercise
Complete the exercise:
LV1M30_Instrument Control Programming
provided inside the moodle course!

Use the VISA API functions to communicate

effectively with an instrument.
Understanding Modularity

LabVIEW Core 1, Module 31

 Agenda
Introduction
What is modularity?
What is a subVI?
Using subVIs
 What is Modularity?
When programming in LabVIEW, complex
programs can be built easily using the variety
of functions provided.
Express VIs and low-level VIs allow us to write
applications, including
Complex acquisition
Sophisticated analysis
Robust data presentation
Flexible file I/O
 What is Modularity?
LabVIEW code is easily-written, easily-debugged,
and can be easily-modified.
Modularity refers to the degree to which a
program is composed of discrete modules, such
that a change to one module has minimal impact
on other modules.
It allows us to buid code faster using reusable
pieces.
It allows us to change the code quickly in one
location.
 What is Modularity?
Type definitions are an example of creating
modular controls, indicators, and constants.
Changing a type definition in one place,
changes all instances of it automatically.
Modules in LabVIEW are called subVIs.
 What is a SubVI?
A subVI is a VI that has been configured to run
within another VI.
It can be placed on the block diagram and it
appears with a customizable icon.
It can also be configured to pass data in and
out.
 What is a SubVI?
SubVIs correspond to subroutines in text-
based programming languages.
The upper-right corner of both the front panel
and block diagram displays the icon for the VI.
 Using SubVIs
One use of subVIs is centralizing code into a
discrete module.
Demo: select code and Create subVI
Next step: customize icon and rearrange the
connector pane (later module)
 Quiz
Modularity refers to the degree to which a
program is composed of discrete modules,
such that a change to one module has
minimal impact on other modules.
a) True
b) False
 Quiz
Which of the following are modular elements
of LabVIEW code?
a) SubVIs
b) Type definitions
c) Built-in LabVIEW functions
d) All of the above
 Quiz
A subVI is a VI that has been configured to run
within another VI.
a) True
b) False
 Quiz
Which of the following is true when creating a
subVI?
a) The code within it is replaced on the block
diagram with a subVI containing a default icon.
b) The wires required to run into and out of the
subVI have been automatically arranged to the
connector pane.
c) The subVI has a customizable icon
d) All of the above
 Quiz
SubVIs can be used to perform a task and
return a result.
a) True
b) False
 Exercise
Complete the exercise:
LV1M31_Understanding Modularity
provided inside the moodle course!

Identify elements that make an effective subVI

and convert a piece of code into a subVI.
 Building the Icon
and Connector Pane
LabVIEW Core 1, Module 32
 Agenda
Introduction
Why do we use the Icon and Connector Pane?
Creating an Icon
Setting up the Connector Pane
 Why do we use the Icon and
Connector Pane?
When programming with modularity in mind,
we almost always need to use subVIs.
To effectively use a VI as a subVI, we need to
create a meaningful icon and well organized
connector pane.
Every VI has an icon associated with it, which
is displayed in the upper-right corner of the
front panel and block diagram.
 Why do we use the Icon and
Connector Pane?
The icon is a graphical representation of a
subVI that identifies it on the block diagram of
another VI.
The connector pane defines the input and
output terminals of our subVI when it is
placed on the block diagram. These are
required to pass data into and out of a subVI.
 Creating an Icon
Once we've opened or created a VI to be used
as a subVI, the next step is to customize the
icon.
Demo: modify the previous example by
replacing the Case Structure with a subVI.
It simplifies and cleans up the Block Diagram;
Code can be easily used in another place.
Open the subVI by double-clicking it, right-
click the Icon and select Edit Icon.
 Creating an Icon
Demo: modify the Icon:
Select a template with two boxes;
Fill the upper box with red;
Save as Template: Red Box;
Enter Text;
Modify Layers and Opacity.
Click the Help button for more information.
 Setting up the Connector Pane
Once we've created the icon, the next step to
configuring a VI to work as a subVI is to define
connections on the connector pane.
Each rectangle on the connector pane
represents a terminal.
By default, a subVI created from existing code
will be generated using the default pattern,
which is this one:
 Setting up the Connector Pane
If we need to add more inputs or outputs than
can be handled by this pattern, we can select
a different pattern by right-clicking the
connector pane and selecting patterns from
the shortcut menu.
In general, we should avoid using connector
panes with more than 16 terminals.
Demo: Rearrange terminals of our subVI.
 Setting up the Connector Pane
In general, top terminals are reserved for
references, or the main input to a subVI.
Bottom terminals are usually reserved for
error clusters.
 Quiz
Where on the front panel and block diagram
are the icon and connector pane located?
a) Upper-left corner
b) Upper-right corner
c) Bottom-right corner
d) Bottom-left corner
 Quiz
The connector pane is defined on the block
diagram of a VI.
a) True
b) False
 Quiz
Which is a tab in the Icon Editor?
a) Layers
b) Icon Text
c) Glyphs
d) All of the above
e) None of the above
 Quiz
A subVI is represented by its icon on the block
diagram of another VI.
a) True
b) False
 Quiz
It is important to have a meaningful icon and a
well-organized connector pane for your
subVIs.
a) True
b) False
 Exercise
Complete the exercise:
LV1M32_Building the Icon and Connector Pane
provided inside the moodle course!

Create an example VI with a descriptive icon and

properly arranged connector pane.
 Using SubVIs

LabVIEW Core 1, Module 33

 Agenda
How do we place and open a subVI?
Terminal settings
Handling errors in subVIs
 How do we place and open a subVI?
Demo:
Method 1:
Block diagram, Select a VI on the functions palette,
select a subVI and place it on the block diagram, wire it
Method 2:
Have the VI open, drag the Icon onto the block diagram
Double click it to open the front panel, to display the
block diagram, hold the Ctrl-Key and double click the
icon
 Terminal settings
When creating subVIs, it is a good idea to
manage the status of the terminals for the
subVI
If there is a subVI which cannot and should not be
run without one of the inputs being wired, the
terminal can be changed to be a required terminal
Demo:
Open a subVI, right-click the desired terminal and
select This connector is required
Required option is only available for inputs
 Terminal settings
If an input is used in an uncritical way, we can
set the terminal to be optional
Here, most of the time the default value is
sufficient to run the VI.
Demo:
Read from Spreadsheet File.vi, Context Help
The short lines without labels are optional
terminals, Click Show optional terminals and full
path
 Handling errors in subVIs
We need to pass errors in and out of the subVI
using the error clusters.
Demo:
Open a subVI and create Error in and Error out
clusters on the front panel
Connect them to the connector pane
On the block diagram, create a case structure covering
all the code
Wire the error in to the case selector, wire the error
through the case and into the error out cluster
 Quiz
How do optional terminals appear in the
Context Help window?
a) Bold text
b) Italics
c) Grayed text
d) Normal text
 Quiz
How do required terminals appear in the
Context Help window?
a) Bold text
b) Italics
c) Grayed text
d) Normal text
 Quiz
The Required option is available for both
inputs and outputs.
a) True
b) False
 Quiz
In which way can a subVI be placed on the
block diagram?
a) Take a selection of existing code and select
Create SubVI from the Edit menu
b) Navigate to a VI via Select a VI on the Functions
palette and double click it
c) Drag the icon of an open VI on the block diagram
d) All of the above
 Quiz
To handle errors in a subVI, error in and error
out clusters are required.
a) True
b) False
 Exercise
Complete the exercise:
LV1M33_Using SubVIs
provided inside the moodle course!

Modify a subVI to handle errors.

Using Sequential Programming

LabVIEW Core 1, Module 34

 Agenda
What is sequential programming
Methods for ensuring sequential order.
How do we use sequential programming?
 What is sequential programming
If pieces of code are not linked by wires, they will run in
parallel.
Most VIs accomplish tasks in a sequential manner.
Read data from a device
Prompt the user to make a change to the system
Read data again
Prompt the user again
Here, all parts would run in parallel
Methods for ensuring sequential order
Create a data dependency in the code
Wiring the error cluster through VIs and subVIs is
a very common and preferred method for
ensuring sequential execution
But, not all VIs and subVIs have error terminals
Methods for ensuring sequential order
Use a sequence structure to force the execution order of the code
The sequence structure is a structure with frames, in which each frame
executes in order.
Demo:
Place a flat sequence structure (stacked sequence structures behave in the
same way) from the structures palette on the block diagram
Add frame after by right-clicking the border
Add frame before the current frame
Delete a frame
Avoid the overuse of sequence structures because they prohibit parallel
execution
 How do we use sequential
programming?
Demo:
Remove the sequence structures from before and
place a case structure instead
Wire the errors through the code
 Quiz
It is only possible to use sequential
programming by connecting error wires.
a) True
b) False
 Quiz
Which of the following features of LabVIEW
automatically enforces sequential
programming?
a) Variables
b) Loop Structures
c) Dataflow
d) Modularity
 Quiz
Sequential programming refers to performing
each task individually and in a certain order.
a) True
b) False
 Quiz
Which of the following methods does not use
sequential programming?
a) Creating data dependencies
b) Using sequence structures
c) Using variables
 Quiz
It is best to use as little forced-sequencing as
possible in order to make use of LabVIEWS
inherent parallelism.
a) True
b) False
 Exercise
Complete the exercise:
LV1M34_Using Sequential Programming
provided inside the moodle course!

Use sequential programming to ensure code

executes in the proper order.
Understanding State
Programming
LabVIEW Core 1, Module 35
 Agenda
What is state programming?
What is a state machine?
Creating a basic state machine
 What is state programming?
Sequential Programming:
Sequence structures and sequentially wired subVIs can be used to ensure
code runs in a desired order
Sufficient for simple applications, but not always the best choice for the
program architecture.

What if the order of the sequence needs to change?

What if we need to stop the program immediately, rather than
waiting until the end of the sequence?
A state programming approach may be more effective than a
sequential programming approach.
A state programming approach allows a program to be easily
modified or expanded.
 State transition diagram
A type of flowchart that indicates the states of a
program and transitions between states.
Bubbles represent states
Lines represent transitions
 What is a state machine?
A state machine is a common and useful design pattern.
State machines implement a state diagram or flowchart.
State machines are commonly used to create a user interface
for a program.
State machines are also used in process tests.
 Creating a Basic State Machine
Demo:
While loop, shift register, enum constant (init, stop) and
make a type def., case-structure
State functionality code implements the function of the code
State transition code determines the next state in a sequence
Create enum constants for each case (to make the
transitions
Add a Timing function
True Constant for the conditional terminal of the while
loop from the Stop Case
False Constant for the conditional terminal of the while
loop from the Init Case
 Quiz
State programming ensures that code always
runs in the same order.
a) True
b) False
 Quiz
Which of the following is true about state
machines?
a) They can only exit when every state has been
visited once
b) A state may map to multiple other states
c) Multiple states may run at the same time
d) States execute in numeric order
 Quiz
A state transition diagram is a type of
flowchart that indicates the states of a
program and the related transitions between
states.
a) True
b) False
 Quiz
How does a state machine transition between
states?
a) According to a pre-set timer
b) As soon as the code in the state is finished
executing
c) Using previous and next buttons activated by the
user
d) By using a transition function to evaluate a
condition
 Quiz
In a state machine diagram, the individual
states are represented by arrows which point
in the direction of the next state.
a) True
b) False
 Exercise
Complete the exercise:
LV1M35_Understanding State Programming
provided inside the moodle course!

Use a state flow diagram to learn about state

programming and state machines.
Using State Machines

LabVIEW Core 1, Module 36

 Agenda
Creating state machines in LabVIEW
Controlling state machines
 Creating State Machines
Demo:
Reuse the last demo; right click the enum
constant, open type def., new items: Acquire,
Analyze and Save between Init and Stop, Save
Type def.
Right-click the case structure, add case for every
value
 Controlling state machines
How can we define different types of state transitions?
Select function to transition between two states
Demo:
Create False constants for the boolean outputs at the unwired cases
Init state: transits to Acquire
Acquire state: transits to Analyze
Analyze state: Select function, Two-button dialog function
 Controlling state machines
How can we define different types of state
transitions?
Using a case structure or select one out of an array
Demo:
Save state, place Array constant, copy the enum type def.
into the array, expand the array to acquire, save and stop
Index Array Function
Place one-button dialogs into init, stop and acquire to
display text
Place three-button dialog into
save to simulate state transitions
 Quiz
To add new states to the state machine, we
simly add new items to the enum constant
a) True
b) False
 Quiz
What does the state machine use to keep
track of the state during execution?
a) Enum Constant
b) Iteration Terminal
c) Shift Register
d) Local Variable
 Quiz
The While Loop used to create a state
machine ensures that each state executes only
once.
a) True
b) False
 Quiz
What is the best way to ensure that the state
machine is easily scalable?
a) Ensure that the shift register uses default values
if unwired
b) Use a type definition for the enum control
c) Ensure that each state only maps to one other
d) Turn the While Loop into a type definition
 Quiz
Which of the following are not required for
building a state machine in LabVIEW?
a) Array
b) While Loop
c) Shift Register
d) Type-defined enum
e) Case structure
 Exercise
Complete the exercise:
LV1M36_Using State Machines
provided inside the moodle course!

Create a State Machine in LabVIEW.

 Parallelism

LabVIEW Core 1, Module 37

 Agenda
Introduction
What is Parallelism?
Avoiding Data Dependencies
 What is Parallelism?
We often need to program multiple tasks so
that they execute at the same time.
LabVIEW will run tasks in parallel whenever
there is no data dependency between them.
 What is Parallelism?
Demo: modify the example:
Add Stop button to second loop
Add Two Button Dialog to first loop
Run the VI
 Avoiding Data Dependencies
Passing the data between the loops without
creating a data dependency can present a
challenge.
Demo:
First attempt: wire a boolean control to both loops;
Run the VI with Highlight Execution enabled.
Second attempt: place the Boolean control in the first
loop and wire its output into the second loop.
Run the VI with Highlight Execution enabled.
 Avoiding Data Dependencies
A third attempt might lead us to try writing
the value of the Boolean from loop 1 into a
file, read that file in loop 2, and wiring the
value into the conditional terminal in loop 2.
A method which would solve our problem
involves finding the location in memory where
the Boolean button data is stored, and reading
that memory location directly.
 Quiz
When two tasks are configured to run in
parallel, they cannot interact with each other.
a) True
b) False
 Quiz
When does LabVIEW automatically run tasks
in parallel?
a) When parallel processing is enabled in the
Options menu
b) When there is no data dependency
c) When the computer executing the code has
multiple processors
d) When the tasks are wired together
 Quiz
Variables break the dataflow programming
paradigm.
a) True
b) False
 Quiz
Which of the following is true about
parallelism?
a) Variables may be used to pass data between
parallel tasks
b) Parallelism can only be done by repeatedly
reading and writing to a temporary file
c) Parallelism can be easily activated by wiring
together parallel tasks
d) When the tasks are wired together, they will run
in parallel
 Quiz
A single Boolean terminal can stop two loops
running in parallel
a) True
b) False
 Exercise
Complete the exercise:
LV1M37_Parallelism
provided inside the moodle course!

Build a VI that demonstrates parallelism and

data dependency.
 Variables

LabVIEW Core 1, Module 38

 Agenda
Introduction
What are Variables?
What are Local Variables?
What are Shared Variables?
 What are Variables?
Creating parallel tasks in LabVIEW is easy, but
stopping them at the same time requires
careful attention.
How then, can we communicate data between
parallel loops without creating data
dependencies?
 Variables
Variables pass data from one place to another
without wires.
Allow us to create complex programs that take
advantage of multi-core processing.
Variables are block diagram elements that
allow us to read data from more than one
place in our code.
 Variables
Local variables:
Store data in front panel controls and indicators
Single-process shared variables:
Store data in different ways
Functional global variables:
Store data in While Loop shift registers
 What are Local Variables?
We can use a local variable to pass data
between loops in a single VI.
Demo: right-click the Boolean control in our
previous example and selecting Create and
then Local Variable.
Right-click and select Change to Read.
Change the Mechanical Action to Switch.
 What are Local Variables?
Demo: create another Local Variable, place it
outside the loops, set it False and wire it to
both loops.
 What are Shared Variables?
Local variables work for communicating data
between loops in a single VI, but what if we
want to communicate data between VIs?
Shared variables share data among multiple
VIs.
To terminate While Loops running in separate
VIs, a shared variable can be used with only a
single Boolean control.
 Shared Variables
They are similar to a local variable, but can
also be used to share data across a network.
They can be single-process or network-
published.
 Shared Variables
Demo: create two VIs with one loop each, similar
to the last example.
Create a new project and add both VIs.
Right-click My Computer and select New and
then Variable.
Select Single Process under Variable Type.
Change Data Type to Boolean and Name to Stop,
click OK.
Save the Library.
 Shared Variables
Drop a shared variable shell, from the Structures
palette, onto the block diagram of our first example,
click inside the shell and select the variable.
Move it into the loop and copy it in the second loop.
Change Access Mode in the first loop to Write, wire it
to the Stop button.
Wire the variable in the second loop to the Conditional
Terminal.
Create another instance of the variable outside Loop 1,
initialize it with a False constant and wire the Error
Cluster.
 Quiz
Variables pass data from one location to
another without connecting them with a wire.
a) True
b) False
 Quiz
Which of the following is not a type of
variable?
a) Single-Process Shared Variable
b) Local Variable
c) Type-Defined Variable
d) Functional Global Variable
 Quiz
When creating variables, it is best to not
initialize them with a value in order to save
memory.
a) True
b) False
 Quiz
Which of the following is a type of shared
variable?
a) Dynamic Shared Variable
b) Static Shared Variable (SSV)
c) Relational Database Shared Variable
d) Network-Published Shared Variable
 Quiz
Local variables can only be used to pass
information within a single VI.
a) True
b) False
 Exercise
Complete the exercise:
LV1M38_Variables
provided inside the moodle course!

Use local variables to write to and read from a

control.
Functional Global Variables

LabVIEW Core 1, Module 39

 Agenda
Introduction
What is a Functional Global Variable?
Using Functional Global Variables
 What is a Functional Global Variable?
A functional global variable is an alternative to
a shared variable.
Shift Registers retain the last piece of
information stored if uninitialized.
 What is a Functional Global Variable?
We can use this to our advantage so that
information is stored, but we also get all the
processing and manipulation abilities of a
subVI.
 What is a Functional Global Variable?
To create a functional global variable, we
place a loop in a subVI and use a shift register
to store data that can be read from or written
to, as is the case with a shared variable.
 Functional Global Variables:
Re-entrancy
A functional global variable is a subVI that
must not be set to be re-entrant.
The same copy of the subVI will be used when
called from multiple locations.
This can help prevent race conditions.
 Using Functional Global Variables
Many VIs that perform measurement and
automation require some form of timing.
A functional global variable has an action
input control that specifies which task the VI
performs.
The shift register needs a While Loop to
contain it, although the loop will run only
once.
 Using Functional Global Variables
Demo: Reset Time
 Using Functional Global Variables
Demo: Elapsed Time
 Quiz
When using functional global variables, enums
are the best way to determine which action to
execute.
a) True
b) False
 Quiz
Functional global variables use which of the
following to store their data?
a) For Loop
b) Shift Register
c) Sequence Structure
d) Case Structure
 Quiz
Every instance of a functional global variable
will call the same subVI.
a) True
b) False
 Quiz
Which of the following is not used in
functional global variables?
a) While Loops
b) Case Structure
c) Shift Registers
d) File I/O
 Quiz
In which case can functional global variables
be used?
a) Reading Values
b) Writing Values
c) Performing Calculations
d) All of the Above
 Exercise
Complete the exercise:
LV1M39_Functional Global Variables
provided inside the moodle course!

Use a timing functional global to perform

multiple actions, including recording the start
time and calculating the elapsed time.
 Race Conditions

LabVIEW Core 1, Module 40

 Agenda
Introduction
What is a Race Condition?
How can we avoid Race Conditions?
 What is a Race Condition?
Weve discussed in a previous modules how
parallelism is a benefit which comes from
LabVIEWs dataflow architecture.
We also investigated how variables can be
used in order to pass data between parallel
tasks.
 What is a Race Condition?
However, variables must be used with care.
Since they break from the dataflow approach,
and allow us to write data in multiple
locations, there exists a very real possibility of
accidentally overwriting our data.
 What is a Race Condition?
Race conditions describe when data is
accidentally overwritten due to the timing of
events or scheduling of tasks.
Race conditions are a common problem for
programs that execute multiple tasks in
parallel and share data between them.
 What is a Race Condition?
Demo: create VI that produces race
conditions:
 Race Condition
They are difficult to identify and debug
because the outcome depends on the order
tasks are executed.
This order is random.
Enabling execution highlighting can hide the
problem!
 Avoiding Race Conditions
1. Control and limit shared resources.
2. Identify and protect critical sections within
the code.
3. Properly sequence instructions.
Most common when two tasks have both read
and write access to a resource.
 Avoiding Race Conditions
Most common resources are shared data
storage, such as variables.
Other resources include files and references to
hardware resources.
Resources altered from multiple locations
makes a race condition possible.
 Avoiding Race Conditions
Try to use only one writer or controller for a
shared resource.
 Avoiding Race Conditions
A second method for avoiding race conditions
is protecting critical sections of code.
Critical code is code that must behave
consistently in all circumstances.
 Avoiding Race Conditions
When using multi-tasking programs, one task
may interrupt another.
If this alters a shared resource that the
interrupted task assumes is constant, a race
condition occurs.
Solution: place critical code in non-reentrant
subVIs (Functional Globals)
Another possibility: Semaphors
 Avoiding Race Conditions
Example:

Outcome 1: Value = (Value x 5) + 2

Outcome 2: Value = (Value + 2) x 5
Outcome 3: Value = Value x 5
Outcome 4: Value = Value + 2
Solution: enforce proper sequential
programming!
 Quiz
Why are race conditions hard to debug?
a) They depend upon the order in which the
operating system executes scheduled tasks
b) They depend upon the timing of external events
c) Use of execution highlighting will hide the race
condition
d) All of the above
 Quiz
How can you avoid race conditions?
a) By controlling and limiting shared resources
b) By identifying and protecting critical sections
within our code
c) By properly sequencing code
d) All of the above
 Quiz
Race conditions are most common when two
tasks have both read and write access to a
resource.
a) True
b) False
 Quiz
What are two of the most effective methods
fro protecting critical sections of code when
trying to avoid race conditions?
a) Use of sequencing
b) Local variables and disk streaming
c) Use of parallelism and state machines
d) Use of functional global variables and
semaphores
 Quiz
By default, a semaphore allows multiple tasks
to acquire it at a time.
a) True
b) False
 Exercise
Complete the exercise:
LV1M40_Race Conditions
provided inside the moodle course!

Eliminate a race condition in a VI.