We have on site 7 equal Micrologix PLC, controlling 7 equal HVAC system for 7 room. The room have redundant HVAC units. All of them have 2 recirculation fans and some of them show the same fault sometimes.
The PLC's have two analog card and the first one who has the Recirculation Fan#1 have been change (the second card have installed the recirculation fan #2), because it's showing a condition that don't allow the fan run property, and having a redundant HVAC system, I shut down the recirculation Fan 1 and the recirculation fan 2 is able to take the 100% load, normally they work 50% each.
Why the problem is happening in all the stand alone PLC with the same card?
I want to try to do a verification of the grounding, any other suggestion or idea?
The PLC's have two analog card and the first one who has the Recirculation Fan#1 have been change (the second card have installed the recirculation fan #2), because it's showing a condition that don't allow the fan run property, and having a redundant HVAC system, I shut down the recirculation Fan 1 and the recirculation fan 2 is able to take the 100% load, normally they work 50% each.
Why the problem is happening in all the stand alone PLC with the same card?
I want to try to do a verification of the grounding, any other suggestion or idea?