Communication problem

[maypot]

Hi

We have one SLC500 plc controlling the essential functions of a turbine driven generator. The PLC communicates with our Woodward 505 governor through modbus protocol via a prosoft communication card. We had since the last three months two communication failure with the woodward governor and we had to remove power to the SLC500 to resume back communication.
Grateful to have some inputs from forum members.

Bob

 

[ZapSib]

hi,

Is this link wired with a cork resistor (typical value 100 ... 150 ohms) to enhance "resistance" to emc disturbances ?
it shall be first point to check. according to my own experience, it fix such issue 8 times out of 10.

rgds.