Time lost while running multiple VIs

[ararajan]

I am running 3 VIs at the same time, communicating to three devices. The three loops using a different interval for each iteration but they basically run for the same amount of time. However, the .txxt files that the data is saved to shows that one VI has run for a significantly less time than another VI. (1 hour vs 30 mins). Is it possible that the VI that ran for the lesser time did so beause the three sampling could not be done at the same time and it had to wait? Does this mean that the time is not measured when this happens?

Thanks in advance.

[Dennis_Knutson]

Not enough information is provided. What sort of devices? How are they connected? Why 3 separate VIs? Where's your code?

[ararajan]

Hi Dennis,

The devices are a temperature controller, an oscilloscope and an NIDAQ. The VIs just happened to be written that way by someone previously working on it.

I am just curious if running three VIs could potentially do what I had asked, because I am not able to find any info on that anywhere.

[James.M]

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@ararajan wrote:

Hi Dennis,

The devices are a temperature controller, an oscilloscope and an NIDAQ. The VIs just happened to be written that way by someone previously working on it.

I am just curious if running three VIs could potentially do what I had asked, because I am not able to find any info on that anywhere.

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It's really hard to tell what is happening in the code and even what you mean by "run for a significantly less time than the others". How is this measured? Total time, active time, Start-End Time? If time is mysteriously disappearing, is The Doctor involved?

Your VIs should be fine running at the same time unless one bogs down the system, or your instrument communication interferes with each other.

You do know that LabVIEW is great at parallel processing? To better make sure your system is running, and provably improve the system, you could combine the VIs in to one application for your system.

Edit: And please provide the code, or simplified version of the code, for more assistance. We need more info.

[crossrulz]

How are these instruments connected?  GPIB?  Ethernet?  USB? Telekinesis?

How are they logging your data?  How is it that you know how long one ran for?  Was there any errors?

[ararajan]

crossrulz, by GPIB. Im sorry but I dont follow what you mean by "how" the data is being logged. The loops are timed in intervals. The total time is recorded against each measurement in the .txt file. Opening the .txt files corresponding to the VIs showed that one ran for lesser time. No errors.

James, I have no idea on how Labview works. I am workin gon debuggin this but I just wanted to make sure that I was solving the right problem. Thanks for your input 😃

I will put up the codes as soon as I have access to them.

[James.M]

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ararajan wrote:

I will put up the codes as soon as I have access to them.

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That's probably best.

It sounds like you're looking at the data that was collecting and seeing less data from one of the VIs. Could this be because the VI was started at a different time? Do the VIs stop themselves after a while based on the instrument? It seems weird that you wouldn't be able to tell why a VI wasn't running for as long as another VI as this would point towards either an internal timeout, or an external actor.

[Dennis_Knutson]

GPIB does not permit execution in parallel so one loop could very easily block another.

[ararajan]

James, they were started at a different time, but only because they were separate VIs. So the time lost was just the time needed to switch between them. No, we stop the VIs whenever we want it to.

Dennis, thank you. That was what I was looking for. I just wanted to make sure I understood the real problem. I'll make sure to mention more info next time so as not waste anyones time. 😃

Thanks all

[Bob_Schor]

We really need to see (and test!) the code.  Do not post a picture of the code (unless we can actually run it from the picture).  If you've got multiple VIs, attach a ZIP of the whole thing.

Bob Schor