DAQmxStopTask hangs when no reference trigger seen

[IChodera]

I have created an analogue input task with a digital input reference trigger.

The analogue inputs are on a couple of 6110 cards linked by a RTSI cable

If the reference trigger is not seen (i.e doesn't occur), the call to stop or clear the task using DAQmxStopTask or DAQmxClearTask does not return.

The problem only occurs on real hardware, running the program against simulated devices works.

[Chris_Garratt_NIUK]

Hi IChodera,

I would like to help you get your problem solved.

There have been several instances of the DAQmx Stop Task.vi hanging in the past with different versions of DAQmx for different reasons.

Can you tell me what version of DAQmx you are using? Problems have been reported with ver. 8.7.

Best Regards,

Chris

[IChodera]

I am using version 9.2.2 - program interface using C++

The problem is almost certainly to do with the reference trigger. If I don't define a reference trigger the DAQmxStopTask call returns as expected.

[Chris_Garratt_NIUK]

Ok, thanks for getting back to me.

I'll look into this for you.

Best Regards,

Chris

[IChodera]

Thanks, if you want my source code please let me know.

[Chris_Garratt_NIUK]

Yes that might be useful. Feel free to post it.

Regards,

Chris

[IChodera]

Code attached. 

Problem occurs when ModifyAcquire is used

[Chris_Garratt_NIUK]

Hey IChodera,

Thanks for posting your code. I'm not an expert with text-based DAQmx so it may take me a little while to get my head round it but shouldn't take too long.

Best Regards,

Chris

[IChodera]

No problem

I have reduced it down as much as possible. The place to start is "ExampleProblem" which sets up an acquire task, then tries to clear it and change the parameters. This is when the problem occurs. Either a call to DAQmxStopTask or DAQmxClearTask (as in ModifyAcquire) locks up if no reference trigger is seen.

[Chris_Garratt_NIUK]

I may try and recreate the code in LabVIEW. It should be identical as the functions called are the same.

Regards,

Chris