Communication Via Rs485; Integrating Inverters Into A Bus System Via The Rs485 Interface - Siemens SINAMICS G120 CU240B-2 Operating Instructions Manual

Connection to a fieldbus

6.4 Communication via RS485

6.4 Communication via RS485
6.4.1

Integrating inverters into a bus system via the RS485 interface

Connecting to a network via RS485
The Control Unit has a two-section terminal strip on its lower side which allows the inverter to
be integrated into a bus system via the RS485 interface. This connector has short-circuit
proof, isolated pins. You will find the terminal assignments in the following table.
Table 6- 19
Contact
1
2
3
4
5
General specifications and requirements for error-free communication
NOTICE
When the bus is operating, the first and last bus station must be continuously connected to
the supply.
Note
Communication with the controller, even when the supply voltage on the Power Module is
switched off
You will have to supply the Control Unit with 24 V DC on terminals 31 and 32 if you require
communication to take place with the controller when the line voltage is switched off.
You must switch-in the bus terminating resistor for the first and last participants. The bus
terminating resistor is either located on the lower side next to the RS485 connector or on the
front side of the Control Unit behind the front door, see Chapter Interfaces, connectors,
switches, terminal blocks and LEDs of the CU (Page 51).
You can disconnect one or more slaves from the bus (by unplugging the bus connector)
without interrupting the communication for the other stations, but not the first or last.
130
Assignments for the terminal strip of the RS485 interface
Designation Description
0 V Reference potential
RS485P Receive and send signal (+)
RS485N Receive and send signal (-)
Shield Cable shield
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Inverter with CU240B-2 and CU240E-2 Control Units
Operating Instructions, 07/2010, FW 4.3.2, A5E02299792B AA