Grounding And Termination - ABB ACS 400 User Manual

Grounding and Termination

RS485 Bus
The RS485 network should not be directly grounded at any point. All the devices on the network
should be well grounded using their corresponding grounding terminals.
As always, the grounding wires should not form any closed loops, and all the devices should be
grounded to a common ground.
The RS485 network must be terminated using 120 Ω resistors at both ends of the network. Use
jumper J2 to connect or disconnect the termination resistors.
Termination should not be done on the intermediate stations. See Figure 42 for the proper method
of termination .
Terminated Terminated
Figure 42 Termination for the RS485 link.
Warning! The connections should only be made with the drive disconnected from the
power source.
ACS 400 User's Manual 97