Is there a bottom line on proper termination of the shield/ground wire for modbus comm cable. Is it different for sensors? I've read conflicting articles about this.

 

Here is a link to a terrific article published by EDN Magazine in August, 1996. It's titled 10 Ways to Bullet-Proof RS485 Interfaces.

http://www.edn.com/archives/1996/080196/16df5.htm


In general RS485 communications is a half duplex, two-wire differential communications network. You can run the network with or without a 3rd wire common. It's best to use the 3rd wire common to keep the network from floating, however, running the 3rd wire common is not always available or practical. Without going deeper, I think the article above does an excellent job of explaining RS485 communications.

Donald Lupo