200279 DAQmx error

[jharris66]

Hello,

We see the DAQmx -200279 error during extended runs of continuous acquisition.  We can go for hours without seeing the issue.  I have attached the main blocks of our data acquisiton module (daq_code.c).

Some observations / comments:

• Debug build
• We saw much improvement setting sleep policy to VAL_SLEEP_MORE
• The nSamples value in callback when error occurred appeared to be a value of 8 (at least in CVI debugger).  We had setup the callback to be called every 800 samples.
• We do use remote desktop connections to view extended runs.  Although, it does appear that the issue occurred at least once when RDP was not being used.
• Source module for DAQmx acquisition is built into a DLL.  The application and DLL share a thread safe queue.

Questions:

• Is it advisable to override the default DAQmx buffer size?
• Is it OK to assume that both DAQ1 and DAQ2 will have the same number of samples when Callback function is called?  (since they are synchronized in initialization)
• Is there a way to ignore the -200279 error and not lose the proper order of samples based on channels
• Could the counter task have any impact on AI tasks?

Thanks!

[JLZam]

Hi jharris66,

- You can change the DAQmx buffer size according to your needs.

- It would depend on the device itself, synchronization assures you that they will begin at the same time, but data availability depends on the hardware.

- You could make an exception for the error by handling it.

Please check the following documents to make sure that you can prevent the error from happening:

http://digital.ni.com/public.nsf/allkb/4159A4241B8A24B3862570EC007AB6B7

http://digital.ni.com/public.nsf/websearch/58C3BD58847B7AD286256F19007DEEE6?OpenDocument

Here you can find a way to cancel the error:

http://digital.ni.com/public.nsf/allkb/BF72229C53F7633386256EDD0069331B

Hope this helps