Daisy chaining four terminal RS-485 meters with single twisted twin (shielded) conductors eg. Beldin 9841

[swil]

Hi,

Recently I learnt that meters with four RS-485 terminals can form a serial string with meters that have three RS-485 terminals using Beldin 9841 or equivalent cables:

https://community.se.com/t5/Power-Metering/Connecting-meters-with-3-RS-485-terminals-to-meters-with-...

Where only Schneider meters with four RS-485 terminals exist in a serial string, what is the advantage of specifying Beldin 9842 over Beldin 9841 cables?

Would wiring a single shielded twisted pair  to the D0 (-) and D1 (+), and the shield wire to the 0V (RS-485) terminal of such meters, leaving the shield terminal vacant, compromise performance in any way?

[Charles_Murison · Accepted solution]

Would wiring a single shielded twisted pair  to the D0 (-) and D1 (+), and the shield wire to the 0V (RS-485) terminal of such meters, leaving the shield terminal vacant, compromise performance in any way?

Possibly, while the shield in 4 wire connections is not connected in the meter, it does help to isolate interference. In an environment with electromagnetic interference you will see a difference in performance between the 2 configurations.