NI 9237 FPGA in VeriStand

[joshe]

I have a 9237-bridge amp in a crio 9049 RT running VeriStand with a custom FPGA.  I have set the 9237 Cal Mode to Calibrated and have a 10V external Excitation.  Using a pressure simulator box we are able to set the mv/V sent to the 9237, so 1mV/V setting shows 10mV going into the AI of the 9237 card, and 10mV/V shows 100mV going into the 9237 card, read from a multimeter. The VeriStand application is reporting 10x less than the multimeter.  I can still scale it in VeriStand to the correct pressure, but don’t understand why the 9237 is reporting a 10x factor less than the multimeter.  I would expect the 9237 card to report the same as the multimeter.  Any clarification or suggestions would be greatly appreciated.

[santo_13 · Accepted solution]

My understanding is that the 9237 returns the V/V value instead of the absolute value measured. In this case, since there is 10V excitation and 100mV at the input, this translates into 100mV/10V or 10mV/V and hence you read 0.01 from 9237