Rs485 Communication - Weidmuller Power Monitor Handbuch

Wiring
6.4

RS485 communication

• When using shielded cable for the RS485 transmission line, ground one end.
• Use a class D dedicated earth for grounding. Do not share a ground with other earth lines (Fig. 1).
• For terminal stations of both side including the upper device, termination resistors should be connected.
Power Monitor does not have any built-in termination resistors.
Connect 120 Ω, ½ W or more termination resistor between [A+] and [B-] of the Power Monitor that is
connected to the end of RS485 transmission line. The RS485 transmission line shielded cable should be
grounded at the end Power Monitor end (Fig. 1).
• Make sure that the RS485 transmission line between each unit is connected using a daisy chain
arrangement.
Do not use a splitter (Fig. 2).
• To avoid noise, separate the transmission line from the high-voltage line (power supply, voltage line).
• When using the RS485 interface, only those units can be wired together which are installed in the same
cabinet. Cabling between multiple cabinets is not permitted (basic insulation).
(Fig. 1)
(Fig. 2)
22
only within the same cabinet
1435710000/01/05.13