VISA read error with Proxy Caller

[thosquanta]

When running a VI (built in LV 2015) from test stand (2014 SP1), i get the following error: VISA Read in AG34980A Fetch.vi->Apply_Load_200msAP.vi->Apply_Load_200msAP.viProxyCaller.

This error does not occur when running the VI standalone. The only inputs to the VI are the VISA resource name ("34980A") and the Signal Channels ("2014," a relay channel). I have checked and the VISA resource is properly closed by a previously called VI, so I am unsure of what could be causing this issue.

I've attached the VI's block diagram and the test stand call.

Any ideas?

[Jorr-El]

Are you getting this error when trying to run your sequence from the Sequence Editor? Is the behavior different when you use the LabVIEW Development Environment instead of the LabVIEW Run-Time in the Adapter settings?

You showed the call chain for your error, but what's the actual error code and text?

[Jorr-El]

Also, can you probe the VI, retain wire values, and figure out where in the VI the error is being produced? I would expect it would be coming from this VI:

But I've seen instrument drivers before that were badly written so that if there's an upstream error, that VI produces its own error and wipes out the actual culprit.

[thosquanta]

this is the actual error. i shall check into your other points shortly...

thanks!

 

[thosquanta]

So, yes, this error only occurs when running the sequence from the sequence editor. there are no errors when i run from the Labview Dev Environment.

here is the error as seen in the LabView VI when Test Stand calls it. apologies but i am fairly new to test stand and am not sure how to probe lines when not in the labview dev environment.

 

[Jorr-El]

That's not a problem. 

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@thosquanta wrote:

...apologies but i am fairly new to test stand and am not sure how to probe lines when not in the labview dev environment.

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No problem! Welcome to using TestStand, it's my favorite NI software product by far.

In TestStand you can actually change the LabVIEW Adapter to run your code modules (the LabVIEW VIs you're calling from TestStand) using the LabVIEW development environment instead of the LabVIEW Run-Time engine. Try changing your adapter to the LabVIEW development environment instead of the Run-Time engine and running your TestStand sequence again. The KB below explains how to change your LabVIEW adapter settings.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000YGk8CAG&l=en-US 

Once you have TestStand configured to use the LabVIEW development environment, you should be able to keep your VI open in LabVIEW, drop down probes, breakpoints, etc. and read the values flowing through the wires when TestStand calls your VI.

[thosquanta]

AHA! the issue ended up being related to a buried subVI expecting a very specific input format. HOWEVER, that link you provided will no doubt prove useful in the future and I have bookmarked it accordingly.

Thanks a ton for your help!

[Jorr-El]

No problem! Glad you were able to figure it out.