I have been using an NI 9237 card in a cDAQ 9172 chassis for developing a test system. We are capturing force data from 4 load cells, and this force is used as feedback for controlling stepper motors via two NI 9401 cards. Only recently, the NI 9237 started having problems capturing force data from the load cells. First, I started seeing occasional errors. I swapped out the card with another NI 9237, and this error has not recurred. However, now the measurements look correct for a while, but they suddenly jump to a value that is out of range of the sensor. After this happens, the values never seem to return. This strange behavior seems to occur on some, but not all, of the NI 9237 channels. Different channels are affected from one test to the next. The read function in LabVIEW does not output any error codes. Unplugging the cDAQ and plugging it back in seems to cause the measurements to return to the correct values. I think it is a hardware problem, but I have no idea how to diagnose it. I am running LabVIEW 2011 SP1, and my version of DAQmx is 9.3.5
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