topic Re: Time delays in LabVIEW

Time delays

b_lee — Wed, 08 Feb 2006 16:53:57 GMT

Ok this question may seem really dumb but for some reason my time delays do not seem to be doing anything. Am I missing something here? Do they only work in loops? I have mine inside a flat sequence which is inside a for loop. Why wont it work? Do I need to connect anything besides the time I want it to delay? I am using a Wait(ms) icon, what is going on?

Re: Time delays

Kenny_K — Wed, 08 Feb 2006 17:25:34 GMT

Usually you just wire the number of mx to the input of the Wait ms VI and go from there. Maybe if you submitteed a screenshot or your VI we could take a look at it and see if something else is going on.

Have you tried using the Highlight Execution to see if you are acutally going to the frame that has the wait ms in it??

Kenny

Re: Time delays

altenbach — Wed, 08 Feb 2006 17:27:26 GMT

I have never found an instance where time delays don't delay 😉

Remember that the inputs is in milliseconds, not seconds, so to get a 1 second delay you would wire a 1000 to it.

If you still have problems, please attach your code. 🙂

Re: Time delays

b_lee — Wed, 08 Feb 2006 17:42:05 GMT

I know it does go into it because my equipment reacts to the flat sequence, but the is no delay.

Re: Time delays

altenbach — Wed, 08 Feb 2006 19:06:04 GMT

The delay will only execute if that particular case is active (Signal Generator=1). Is it?

Within that case structure, you cannot predict what starts executing first, the 5000ms delay or the VISA stuff. Most likely they will start virtually simultaneously and the total time spent in that case structure will be the larger of (1) Time to execute the VISA stuff and (2) 5000ms.

Notice that the flat sequence around it does not do anything, you can delete it without change in functionality. Execution order is entirely determined by dataflow alone.

Notice also that your "Numeric 8" increment operation has no data dependency, and will thus complete probably way before anything else in each iteration of the big loop. (You might want to use a shift register instead of local variables here, see: this example for a comparison)