I have 2 I/O panels each with a FP-1601, and FP-AI-112, and an FP-RTD(don't recall the model #) module reading a few low voltage (0-40mV) signals. This test system was left running over the weekend, and upon returning Monday morning, the values the FP-AI-112 Module in Panel #1 was returning were not correct. It appeared that the voltage inputs were bouncing back and forth from full scale to zero and anywhere in between. After measuring with a voltmeter, the actual signals were still in the 0-40mV range, but Module #1 was reporting random values.
I swapped the two FP-AI-112 modules and using Module #2 I was able to read the correct values on the I/O at Panel #1. I replaced Module #1 with a spare module, and everything appeared to be working fine. After leaving the system running for a few days, it seems that the new module is behaving the same way that the originally problematic module was behaving.
Current setup:
Panel #1 FP-1601, FP-AI-112 (Originally from Panel #2), FP-RTD Module
Panel #2 FP-1601, FP-AI-112 (Originally a spare, now not functioning correctly), FP-RTD Module
Not Installed FP-AI-112 (Originally in Panel #1, now not functioning correctly)
Any suggestions or help would be greatly appreciated.