Modbus RTU communications connection

Just working on a job with a heap of Schneider power monitors connected to my PLC with Modbus RTU.


There are the usual D0 and D1 connections plus 0 volt that is being used these days as a 3 wire connection and 0 volt ties all the units together at the one voltage ;level - that is all good.


The Schneider documentation also shows the drain wire of the cable connected to a terminal with an indication of a circle with 2 horizontal lines through it. Have never seen that symbol before.


Would anyone know what it represents at all please? If it is just a loop through connection for the brain wire that is good.


I cannot see it being anything else as there is no earth connection on the meters but who knows.

Can you show a picture of the circle with 2 horizontal lines? It sounds like a slot head terminal screw.

You mean like on this https://docs.rs-online.com/fdb6/0900766b8141a1c0.pdf and page 7/9.


and
https://upload.wikimedia.org/wikipedia/commons/3/3a/WiringSymbols.png


On this it means connector for shield (shielded cable with two twisted pair)?




p.s


On other model wiring it shows that it is only feed throught for shield.


https://www.se.com/ww/en/faqs/FA323145/
and
https://download.schneider-electric...p_File_Name=DESY022EN.pdf&p_Doc_Ref=DESY022EN page 50.

I've not seen that symbol used before but it is clearly the shield.

Thank you muchly - one of the links clearly shows the shield looping through and then grounded. I thought it was a loop through as the meter has no ground connection.