Rockwell Automation 1747-L40 SLC 500 Fixed Hardware Style - Manual (Page 118)

Appendix A
Setting Up the DH-485 Network
A–13
Grounding and Terminating the DH-485 Network
One (only one) of the link couplers at the end of the link must have
Terminals 1 and 2 of the network connector jumpered together. This
provides an earth ground connection for the shield of the communication
cable.
Link couplers at both ends of the network must have Terminals 5 and 6 of the
link connectors jumpered together. This connects the termination impedance
(of 120
Ω
) that is built into each link coupler as required by the DH–485
specification. See the figure below for the proper jumpering.
End-of-Line Termination
Belden #9842 Cable
(1219 m) 4000 ft Maximum
Jumper
Jumper
Jumper
1
2
3
4
5
6
1
2
3
4
5
6