1. Workshop 05
Review

2. Today's Topics

Review of Workshop 05



State Machines
Sequential Structures
Parallel Processing

Documentation

Timing Functions

3. Review Question 1
If I add a new element to an enum that is saved in
a *.ctl file, how would the file need to be saved in
order to update all of instances
a) Custom control
b) Strict Type Definition
c) Type Definition

4. Review Question 1
If I add a new element to an enum that is saved in
a *.ctl file, how would the file need to be saved in
order to update all of instances
a) Custom control
b) Strict Type Definition
c) Type Definition

5. Review Question 2
True or False?
A sequence structure can be aborted in the middle
of the sequence.

6. Review Question 2
True or False?
A sequence structure can be aborted in the middle
of the sequence.
FALSE

7. Review Question 3
•
If you have a Wait Until Next Millisecond Multiple in a
while loop with a 20 wired to it and the other code
within the loop take 25ms to execute, how long will one
iteration of the loop take?
a) 25 ms
b) 40 ms
c) 45 ms
d) unknown
7

8. Review Question 3
•
If you have a Wait Until Next Millisecond Multiple in a
while loop with a 20 wired to it and the other code
within the loop take 25ms to execute, how long will one
iteration of the loop take?
a) 25 ms
b) 40 ms
c) 45 ms
d) unknown
8

9. Review Question 4
1. Which of the following is a state machine?

10. Review Question 4
1. Which of the following is a state machine?

11. Review Question 5
Which block diagram objects compose a state machine?
a) While loop
b) Enum
c) Sequence structure
d) Case structure
e) Shift register
f) Numeric constants
11

12. Review Question 5
Which block diagram objects compose a state machine?
a) While loop
b) Enum (optional, although often used)
c) Sequence structure
d) Case structure
e) Shift register
f) Numeric constants
12

13. Documentation
• Free labels
• (standard) labels
• Descriptions
• Captions
• Tip Strips
13

14. Documentation: Description and Tip Strips
• Descriptions- appear in the
Context Help window when you
move the cursor over the object
• VIs: VI Properties» Description
• Controls, indicators, and constants:
Properties » Description
• Tip Strips
• Brief description of the object to
display when you move the cursor
over a front panel object while a VI
runs. (controls, indicators, and
constants)
14

15. Documentation- Labels and Captions
•
Labels (including free labels) are available on the
front panel and block diagram
•
Captions are only available on the front panel – use
when you want to be more descriptive and…
• don’t want to take as much space on the block diagram
• programmatically use the label and don’t want to break
your VI
•
To create a free label:
• Double-click and begin typing
• Place a free label form the Functions palette
•
Be descriptive!
For example,
• Does “Temp” mean temporary or temperature?
• What are the units of “Temp”?
15

16. Documentation- Block Diagram
Use block diagram comments to:
• Describe algorithms
• Explain the data contents of wires
• LabVIEW 2010 and later: right-click
on wire select Visible»Label
• LabVIEW 2009 and earlier: use a
free label to label wires
• Using Unbundle/Bundle By Name
creates self-documenting code
16

17. Demonstration:
Adding a VI Description and Free Labels

18. Timing Functions
• Control or measure the frequency at which a loop executes
• Provide the processor with time to complete other tasks,
such as processing the user interface
• Uses the operating system millisecond clock

19. Wait Function
• Waits the specified number of milliseconds.
• If 0 is wired to it, the current thread is forced to yield
control of the CPU
• Uses the operating system millisecond clock

20. Wait Function- example cases
• Loop would go to next iteration
after 10 ms or more depending
on amount of time the subVI
takes.
• If subVI takes >10 ms, loop
goes as soon as subVI is done
• If subVI takes <10 ms , loop
goes at 10 ms mark.
• Loop would go on to
next iteration after
10 ms, because the
only thing that
happens in each
iteration is wait 10
ms
Moment next loop
iteration can begin
10 ms
20 ms
30 ms
Wait
Other code
(running in
parallel with
Wait VI)

21. Wait Until Next Millisecond Multiple Function
• Waits until a multiple of the millisecond value wired in
• Provide the processor with time to complete other
tasks, such as processing the user interface
• Uses the operating system millisecond clock

22. Wait Until Next Millisecond Multiple Function
• Loop would go to next iteration
after 10 , 20, 30, or a greater
multiple of 10 ms depending on
amount of time the subVI takes.
• If subVI takes <10 ms , loop
goes at 10 ms mark.
• If subVI takes 16 ms, then
the loop goes at 20 ms.
• Loop would go on to
next iteration after
10 ms, because the
only thing that
happens in each
iteration is wait 10
ms and 10ms is the
first multiple of 10
• If subVI takes 22 ms, then
the subVI goes at 30 ms.
Wait
10 ms
20 ms
30 ms
Other code
(subVI)

23. Comparison of Timing Functions
Red represents
times when Wait
functions are NOT
restricting
Moment next loop
iteration can begin
Other code
(running in
parallel with
waits)
10 ms
20 ms
30 ms

24. THANK YOU !!!