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[star-123]

Hi friends,

How much time one iteration of while loop?

Have a nice work.

[crossrulz]

It completely depends.  What is in the loop?

In short, a While Loop cannot iterate until EVERYTHING inside of it completes.  So if you have a wait for 1 second inside of your loop, the loop will iterate at around 1 second.

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[Dennis_Knutson]

Please use something other than 'LabVIEW' for a subject. Every post here is related to LabVIEW.

Your question does not make much sense. The iteration time is dependent on what is inside the loop as well as the processor in the pc. It is also something that you can easily test yourself. Do you have a specific VI?

[altenbach · Accepted solution]

Do you want to measure the loop time of an existing while loop?

try this:

[star-123]

Is the code for one iteration?

[GerdW]

Did you try it?

(Learning by doing is a concept often used… :))

[altenbach]

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@1085 wrote:

Is the code for one iteration?

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It updates with each new iteration, measuring the time difference since the same code was called the last time, i.e. in the previous iteration.

I typically use a custom format of "%.2ps" or similar for the time display. (right-click...display format...advanced editing mode). This way it displays in nice si units (200.00ns, 12.40ms, 3.12s, etc) 

[Norbert_B]

Also note that execution times depend a lot on the system you use if you have no wait times included in the loop.

Long story short:

You cannot tell in advance how fast a single loop iteration is on your machine until you test it.

Norbert

[NIquist]

In addition the loop time can change from iteration to iteration depending on what background processes are running on your PC.  A virus scanner starting up or an OS auto-update can slow down your loop significantly in some cases.  If you need deterministic operation you'll need a Real-Time PC/OS.

[altenbach]

I think you guys are way overcomplicating the discussion. There was never a question on how to reliably keep a fixed loop time or how to run (or not run) the loop as fast as possible.

All he wanted is to measure the actual loop time (e.g. for benchmaking or validation, I guess).

It was a measurement question, not a control question and consisted of only eight words! 😄

Once the actual measurment results turn out to be puzzling (e.g. too much jitter, longer than expected, etc.) we can revisit this disucssion.