I'm trying to simulate pressure transducers with an output of 3mV/V (excitation is +10V, so full range should be 0mV to 30mV). I'm looking for a high channel-count analog output PXI device (possibly PXI-6723) that does not have the low side of the analog output channels tied to facility ground (differential AO channels). The plan was to use a voltage divider circuit to scale the +/-10V output of the AO card down to +/-50mV. I'm using a 16-channel, 12-bit AO card that has all of the AO commons tied to the PXI chassis ground and facility ground. The DC part of the signal does what I want it to, but there is approx 80-100mVpp of noise riding on it (from the ground connection). I also tried a PXI-6115 card which we had on-hand, and its AO reference is tied hard to chassis as well --- same result with the ground noise. Is the PXI-6723 AO GND isolated from chassis/facility ground? Even if all of the AO GNDs are shared on the board, that solution should be much better than having a noisy ground reference.
Any ideas? Alternate solutions to simulating a floating, millivolt output device?
Thanks!
