Have a constant elapsed time

[franckfischer]

I have several temporizings in my labview program. For a defined temporizing of 10 sec, the real elapsed time could be 7 sec for a program run and 15 sec for another one. How can I be sure that the time programmed will be respected ? I work with Fieldpoint FP-1000; FP 401; FP 300 and Labview 6.0i.

[Aaron Marks]

Not quite sure I understand the question. What are you using to measure time in LabVIEW?

[franckfischer]

I am using the VI "wait X ms" to make temporizations between tasks (done with Fieldpoints modules). For a defined value of X ms, the real elapsed time for a run of the program to another one is not the same, and is not equal to the value I chose.

I hope this is more clear. Don't hesitate to ask me. I have really no solution.

[JohnM]

Use the Wait Until Next ms Multiple VI and encase it in a sequence structure and execute this VI after each cycle of your program completes. Main problem that you are experiencing is that you are not running your program on a deterministic Operating System. The OS you are using is multitasking events, which some events take long to process, which makes your program run long. Using the Wait Until next ms Multiple will do just that, it will wait for the next ms Multiple and then return allowing your program to complete another cycle.

John M

[franckfischer]

Thank you John,

I have tried with wait for the next ms and a while structure. It works. Thank you.

Franck.