Let me hijack this thread a little bit to ask about issues we had with ControlLogix 1756-L82E PLCs and some of modules.
So we had modules stopping communication with CPU. It happened 3 times so far, twice for AMCI SSI card where we caught error code 16#203 pointing out it was communication failure on backplane. We figured out most likely it was happening as our RPI time was 0.5 ms. Later we increased to 2ms. We cannot go slower than this for this process. Module stayed in fault for few seconds before it continued to work.
3rd one was for fast analog input/output card 1756-IF4FXOF2F/B, where we didn't catch an error. Here module stayed in error until client reset it before catching an error code.
So we started adding logic to check the health of the modules and do some appropriate actions based on diagnostics.
My question is does anyone have idea why it might be happening and what is your experience about A-B PLCs having problems like this? I've never experienced something similar with Siemens PLCs, where I have more experience.
Do you usually put module fault handling in your programs? Any tips here for novices like me, who are doing first project with A-B PLCs?