Modbus Communication Unstable


Thread Starter



I have this issue regarding my modbus network, and most of the solution i already try like end resistor and shielding. I have at least 4 different devices in the loop, Power meter, Nt935, sepam and circuit monitor. when i scan using my PMC i can detect some devices. and when use modscan32, i cannot get a response from other slaves which the PMC shows healthy. Anyone experience this kind of issue before? I am using egx200 by square d and I cannot do device list scanning/discovery.

Thank you so much!
1) What is PMC?

2) What does 'detect some devices' as "healthy" mean? Does it mean that you can send a valid Modbus request and get a valid Modbus reply? Or something else?
I have a various Modbus devices such as NT935, sepam relays and motor starters. I can detect sepam on PMC software but on modscan I cannot get a valid response. PMC software is like a Modbus scanning tools that identifies what type of Schneider Modbus devices connected in the loop. I ask around and some of senior colleague of mine told me to play around to the timing both scanning tools haven't try it yet will update once I finished the test.