You must stop your application before the engine can stop

[josborne]

I have a built application that uses LV DSC 6.0.2. The application programmatically starts and stops the tag engine. The application works fine, but on some machines, I will continually get the following dialog when I try to shutdown the Tag Engine:

"You must stop your application before the engine can stop"

This is strange, because it only occurs on some machines (it appears as though it might occur on machines that ONLY have DSC Run-Time installed, not the full LV DSC dev. system).

The dialog seems to be referring to the "control" application that is trying to shutdown the engine... it is not telling me that my device servers need to be shut down.

This dialog seems illogical, I should be able
to build an application that can start and stop the engine... and why do I get this dialog on some machines but not on others?

[Roli · Accepted solution]

John Paul,

There are two points we should consider:
1st: You might have different while loops in your application where you read/write from/to the tag engine with the Read/Write Tag.vi. Those VIs has an output shutdown which should be wired to abord the while loop. If you have some cases where you do not wire this output to your while loop stop you might access the engine while you want to shutdown the engine within another loop with the Engine Shutdown.vi. -> Make sure you have all DSC Engine accessing while loops ended before you shutdown the engine.

2nd: I guess there was once a race condition problem with the DSC engine and how it accessed the shared memory with the Read/Write Tag.vi. But this race condtion should be fixed with the LabVIEW DSC version
6.1 or with the additional fixes for LabVIEW DSC 6.0.2. You could download the fixes (in this case especially the BVRTDatabase.dll) from NI's Driver&Update page : www.ni.com/support/ > Option 3, Driver and Updates > Search Drivers and Updates > type "LabVIEW DSC" > pick LabVIEW Datalogging and Supervisory Control 6.0.2 Fixes.
You need to apply this fixes as well on your DSC 6.0.2 Run Time System!

I hope one of the two suggestions help to solve your issue.

Regards
Roland

ftp://ftp.ni.com/support/labview/labviewdsc/fixes/6.0.2/

[josborne]

Thanks, Roland. The fixes to 6.0.2 appear to have fixed the problem.