Siemens SINAMICS G120 - Communication Via RS485; Integrating Inverters into a Bus System Via the RS485 Interface

Configuring the fieldbus
7.6 Communication via RS485
Inverter with CU230P-2 Control Units
148 Operating Instructions, 11/2013, FW V4.6.6, A5E02430659B AG
7.6
Communication via RS485
The RS485 interface is used to integrate the inverter in one of the following fieldbus systems:
● USS
● Modbus RTU
● BACnet
● P1
7.6.1
Integrating inverters into a bus system via the RS485 interface
Connecting to a network via RS485
Connect the inverter to your fieldbus via the RS485 interface. Position and assignment of the
RS485 interface can be found in Section Interfaces, connectors, switches, control terminals,
LEDs on the CU (Page 60). This connector has short-circuit proof, isolated pins.
Figure 7-8 Communication network via RS485
You must switch-in the bus-terminating resistor for the first and last nodes. The position of
the bus-terminating resistor can be found in Section Interfaces, connectors, switches, control
terminals, LEDs on the CU (Page 60).
Note
During bus operation the first and last bus subscriber must be constantly supplied with power
as otherwise the communication with the other subscribers is broken.
With the exception of the first or last slave, when required you can remove slaves from the
bus. To do this, withdraw the bus connector. When doing this, communication to the other
nodes (stations) is not interrupted.