Suddenly Error -17306 in LV-Operator-Interface after 3 hours when trying to read a StationGlobal

[OnlyOne]

Hello,
i´m using the example-labview-operator-interface with some modifications.
One of the changes is that i created a Thread (UserEcentCallback.vi) which reads a value from the StationGlobals and displays it on the OP.
This thread is running in a loop and executed every second. This worked fine for ~ 3hours and suddenly the attached error-message appeared.

What can i do to prevent this problem?
I´m using the default "TestStand Get Property Value.vi" to read the Globals.

Thanks for all tips.

[RayFarmer]

Hi,

That seems a strange one, especially seeing the VI before it must have found the property ProjectParameter as it read State_Mode without problems.

I guessing ProjectParameter is still present in your StationGlobals after the error occurred!

As to what to do, you could do a Check to make sure the property exists before reading the data.

Regards

Ray

[OnlyOne]

Hello Ray,
the propertys are 100% existing. I dont need to check this because i dont add or remove any propertys during runtime.

My idea is currently to change the "TestStand Get Property Value.vi" by adding  loop over everything, so that i reads again if the first read created an error.
Perhaps the TestStand-Cfg was something like "locked" when i was trying to read the data. Is this possible?

[dug9000]

OnlyOne,

Are you posting this uimessage synchronously? If not then it's possible that the sequence context is no longer being used (and thus no longer has stationglobals attached to it) by the time your code executes. Basically it's a race condition. Make sure you are passing True for the synchronous parameter to postuimessage.

Another thing you can do if you don't want to post the message synchronously is to get the station globals from the engine (you'd need to pass a reference to the engine into this vi if it doesn't already have one).

Hope this helps,
-Doug

Message Edited by dug9000 on 09-07-2007 10:07 AM

[OnlyOne]

Hello dug9000,
you are right, all synchronous parameter in the postuimessage  are FALSE, now i changed them to TRUE and now it seems to run better.

Thanks for that tipp