3 months into the PLC game, so please excuse my ignorance. I'm troubleshooting a level input that sporadically freezes on a PLC 5/20E. It is reading this input from a MSG instruction on a 1756 L72 Contrologix. The level on that controller is always updating normally. The message instruction comm details are DH path, Ch. A destination, node 74. I have a DH module fault on the contrologix, "no connection instance 16#ff00." "BDH2 only Node"
The manual on this module based on the conditions states to check cabling. This is where I could use some guidance. Would this be something regarding the resistor? What ohms/signals should I have coming from the logix and at the PLC? Since it's only a few wires, I'd imagine other things on this comm path would be affected as well.
I'm leaning towards a cable signal issue on this trunk line, however I'm not ruling out something in the logic going wacky. I am aware of the math overflow fault as well.
Any pointers would be greatly appreciated!!!
The manual on this module based on the conditions states to check cabling. This is where I could use some guidance. Would this be something regarding the resistor? What ohms/signals should I have coming from the logix and at the PLC? Since it's only a few wires, I'd imagine other things on this comm path would be affected as well.
I'm leaning towards a cable signal issue on this trunk line, however I'm not ruling out something in the logic going wacky. I am aware of the math overflow fault as well.
Any pointers would be greatly appreciated!!!