DAQmxErrorADCOverrun error on OEM USB 6221

[Lou_III]

I create an analog task with 2 channels (ai1, ai2) on the USB 6221 OEM card.  Everything works fine except when I stop the task I get the error -200019 (DAQmxErrorADCOverrun) reported by the call to DAQmxStopTask.  I am using V8.9 without Patch 1 as the info says it is not necessary for this card (the patch is not yet available as part of a RunTime5 install, or so I am told).  I collecting data at only 200 Hz and I am not letting the FIFO pile up or anything.  I can do one channel at 100 KHz no problem.  I only get the error when collecting 2 or more channels on this card.  Anybody know why I am getting this error or is it bogus?   I am also running a single channel data collection on a PCI 6220 at the same time and this never reports any errors.

Thanks for any help,

Lou III

[lab_boy]

Hey

Check this knowledgebase, this might help you.

Cheers

-lab

[Lou_III]

Thank you for your response.  The USB 6221 is being externally clocked but only at 200 HZ from the sample clock of a PCI 6220.  I export the clock onto a PFI line of the 6220 and then I have physically wired it to a PFI line of the 6221.  I have purposely set the "sample rate" and the "number of points to collet" to huge values in the DAQmxConfigureSampClkTiming function call so the buffer created should be huge.  I am only collecting data for a few seconds and I am always streaming it off so I'm not sure how the buffer would every overrrun itself.  Again, it only happens when I collect more than one channel.

[lab_boy]

Hey,

Can you please post your code, please try to post the simplest version i.e. only the DAQ, I will try on my DAQ card and see if the error is reproduced.

Cheers

Lab