TestStand can't find variable once in thousand Set calls, "Error -17306"

[Bill2@NGC]

Hello All,

I'm getting this strange error after running this code successfully 10's of thousands of iterations,

"Error -17306 occurred at Unknown variable or property name 'Exit_Test'.
Error accessing item 'StationGlobals.Exit_Test'. in TestStand - Get Property Value (Boolean).vi->StopTestPopup1.vi->StopTestPopup1.vi.ProxyCaller

I've recreated a simple version of my code and attached it.  It just loops around counting numbers and waiting for the test operator to end the test.  In the real system we are testing the device, of course.  But once in a while (days for the real system, and several minutes for the attached code), it says it can't find the StationGlobal that it just successfully used.  The error happens at the Set Property Value.vi.

Do I need to add a delay between the Get and Set?  By the way, in the real system, the delay between each loop is 500ms.

Thanks for your help.

Billy

[~jiggawax~]

Hey Billy,

I reproduced your error.  I do think it is trying to access the variable to quickly.  I believe you are seeing race conditions between your sequence and the VI.  The weird thing is I don't get the error if I place a delay in the loop in the VI.  But the error happens right away if there is not a delay.  Have you seen this error out in the "real system?" 

Regards,

[~jiggawax~]

Thought you might be interested in this...... http://zone.ni.com/devzone/cda/epd/p/id/6138

Also, doing it the other way.... http://forums.ni.com/ni/board/message?board.id=330&thread.id=20866

Regards,

[Bill2@NGC]

Hi Jigg,

Thanks for info.  I would like to try both of the techniques, but sendnotifiertoteststand.zip doesn't lead anywhere (i.e. I can't download it), and I have TS 4.0 and after downloading the 2nd example, I can't run it. 

So can you release the 2nd example in TS 4.0, and/or fix the download of sendnotifiertoteststand.zip?  Thanks very much.

Billy

[Bill2@NGC]

I forgot to answer your first question, about the "real system".  It does happen, and we do have a 500ms delay in it.  It ran correctly for days, 24 hours a day, before the error occurred.  The simple version I sent out, has 11ms delay so the error occurs much more often.

[RayFarmer]

Hi,

I would have a small delay in the loop just so that the loop is not hogging all the process time.

Or better still use an Event frame.

Next I wouldn't keep writing back to TestStand unless you actually press the Stop Button.

Regards

Ray Farmer

[~jiggawax~]

I back saved it to 4.0.  Hopefully that will work for you.

Message Edited by ~jiggawax~ on 06-02-2009 06:30 PM

[Bill2@NGC]

Hi Ray and Jigg,

The little Delay vi is just a call to the Std LV Wait vi.  We created that so we would know when the delay would be executing without having to use a Stack Seq.  Thanks for reminding me about using events only writing to TestStand on value change.

Thanks for the Notification example.  I changed the last one to a GetStatus rather than a Wait, and put a while loop around it to simulate my real test of repeated testing until test conductor says we're done.  And I noticed that after working correctly the once time, if I ran it again without restarting TestStand, the 1st Wait would immediately trigger before any buttons were pushed.  I had to put a Clear after the Create to get this to always work.  Why does it do that?

Billy

[Manooch_H]

Hi All,

I have been trying to reproduce the original error but have not had any luck. I've been using TestStand 4.0 as well as TestStand 4.0.1 with LabVIEW 8.5.1.  Could you please tell me what versions of TestStand and LabVIEW you have used to reproduce this? Also, how long should I expect the sequence to execute before receiving the error?

Jiggawax - you mentioned that you were able reproduce the error and it happened almost immediately. Would you mind posting the files that you used to reproduce the error as I am unable to reproduce it with the originals files?

Thanks!

[Bill2@NGC]

Hi Manooch,

I have TestStand 4.0 and LV 8.5.  I think my original attachment, failed to include the Delay.vi, which is just a call to the Wait VI.  With a Delay of 11ms, it would occur randomly after running for a few minutes to almost an hour. 

Billy