Hello. I have a +/- 100 mV signal that I would like to read using the FP-AI-V100m module (0-100mV range). Can I use this module for this purpose? I'd use the FP-AI-V5B module that has the +/- 5VDC range, but I need the sub-millivolt range.

[Aaron_G]

The FP-AI-V100m can be used with a +/- 100 mV signal without causing damage to the FP-AI-V100m, but the signal will only give you a valid reading when it is in the 0 to + 100mV range. Whenever the signal is negative, you will receive a reading of 0 and an error message stating "Out of Range". The easiest solution is to go with the FP-AI-V5B, or to use the FP-AI-100 or FP-AI-110 I/O modules (they have bipolar voltage ranges of +/- 1.2 V and +/- 0.065 V respectively).

Alternatively, it is possible to use a summing amplifier to deliberately introduce a known, positive offset (I.E. 100 mV) and use the FP-AI-V1 since the range would then always be positive. However, this will require additional external hardware, and would introduce additional sources for error/noise.