This document provides an overview of programming a robot using LabVIEW for FIRST Robotics Competition. It discusses what LabVIEW is, how to get started with a new project, and where to find code examples. The main content demonstrates how to program a tank drive robot with two joysticks controlling four motors. It shows initializing the motors in Begin.vi, reading the joystick values in Periodic Tasks.vi, and passing the values to a tank drive block to control the motors. Global variables are also introduced as a way to store and access sensor values from anywhere in the code.

1. Basic LabVIEW
Kristina Landen
FRC 2093 Bowtie Brigade
knlanden@gmail.com

2. Who has heard of or used
LabVIEW before today?

3. Who has ever programmed in
another language before?

4. Has anyone ever programmed
for FRC before?

5. Overview
O What is LabVIEW?
O Get familiar
O Code 4 wheel tank drive by PWM
O Add actuator, controlled by buttons
O Global Variable benefits and usage

6. What is LabVIEW?
O Visual – no endless lines of code
O Easy to follow
O .vi – Virtual Instrument

7. Getting Familiar with
LabVIEW
At this point, I will leave the presentation, and go into
LabVIEW and explain things in there. The following
slides are what I covered.

8. Getting Started
O Open LabVIEW
O On the “Getting Started” window, select
“FRC cRIO Robot Project.” This will be
what you use for all of your code involving
the robot.
O Name your project something memorable.

10. Project Explorer
O Direct links to all of the .vi’s in your
program
This is where your team
number will go so the
code knows what it is
talking to.
Under “Team
Code” is where
you will find the
majority of the .vi
files you will need
to program the
robot.

11. Begin.vi
O This is where all of the things you will be
coding are initiated.

12. Finish.vi
O This is where you terminate all of the
things you setup in Begin.vi.
O This is important because if not done,
things on the robot don’t shut down
properly and can cause code issues later
on.

13. Teleop.vi
O This is where you can write code to make
the robot complete tasks, but is not
always the best place to do so.

14. Teleop.vi Continued
O You can put display messages to the
Driver Station here which will display
when Tele-operated mode is enabled.
This message is the name of the project
that I am working on.

15. Periodic Tasks.vi
O This is where I do the majority of my
programming
O Sensor data gathered here can be utilized
in Autonomous mode as well as in Teleoperated
O You can control how often sensors are
checked for data

16. This is where
you will be
putting code for
driving and
sensors.
If you plan to use pneumatics,
delete this Disable Structure
and fill in the refnum name and
set it up in Begin.vi and
Finish.vi.

17. Where Do I Get .vi’s?
O Right click – WPI Robotics Library
O WPI Robotics Library has all of the FIRST
related .vi’s needed for competition. You
will have to use .vi’s from the
“Programming” category to complete your
code.

18. WPI Robotics Library

19. Examples
O Where to find them
O How to adapt them to fit your code

20. In Each Example There Is…
O Initialization of ports and channels
O Closing of ports and channels
O The stuff that makes everything happen
O Bonus blinking lights, pretty graphs, and
other switches and dials

21. What We Have To Do…
O Recognize which part is which
O Figure out which part to put in our code
O Decide which parts to omit
O Replace inputs and outputs with Joysticks
and Motor blocks

22. Global Variables
O Robot Global Data.vi
O Store all sensor values, joystick values,
etc.
O Can be used ANYWHERE in the code
O Can save a lot of time
O Instead of writing the code for buttons on a
joystick each time you want to use one,
use global variables written to in Periodic
Tasks.vi

23. Let’s Program!!

24. By the end you will be able to…
O Program a 4 wheel tank or arcade drive
by PWM
O Program another actuator motor using
buttons
O Pass the name of your program to the
DriverStation

25. Programming Drive Motors: Begin
Before
To replace one block with
another, select the block,
right click, replace. To
After
replace a “Open 2 Motor”
with an “Open 4 Motor”,
Highlight the code for one
continue and go “Robot
joystick and copy it by
Don’t forget to change the name too!
Drive Palette, Open 4
holding control and
Motor”. Add constants to
dragging. Change the
the open ports below the
USB constant by clicking
pre-existing ones by right
it, and selecting USB 2.
clicking the hub, create,
constant.

26. Programming Drive Motors:
Finish
Copy the Joystick
close from below
and change the
name.

27. Programming Drive Motors
This is the basic
program setup for a
2 Motor Drive
chassis. However, it
is setup to run two
motors with one
joystick.

28. Programming Drive Motors
Copy the code for
Joystick 1 up, rename it,
then wire into the
“Unbundle” block.
(This is what the big red
arrow on the last slide was
pointing to) 
Expand the “Unbundle” block.

29. Programming Drive Motors
Tip: To expand a while
loop, hold control,
click, and drag where
you want more space.
Insert an “Unbundle”
block from
“Programming>Clust
er, Class, and
Variant>Unbundle”
and wire the input to
the pink pipe that
runs through the
while loop.

30. Programming Drive Motors
“WPI Robotics LibraryRobot Drive- Joysticks
and get the “Get” block.
“Unbundle by Name”
from ProgrammingCluster, Class, and
Variant wired to “axis”

31. Programming Drive Motors
Wire the pink pipe from the “Unbundle”
to the Tank Drive in order to transfer the
information from Begin to here.
Get a “Tank Drive” block
from WPI Robotics
Library- Robot Drive- Tank
Drive. Wire the outputs
from the Y axis of the two
Joysticks into the Right
and Left motor ports.

32. Thank You For Listening!!
Questions?
knlanden@gmail.com
503-853-6704