Assignment Of The Interface - Siemens SICAM P 7KG7750 Manual

1.6.3

Assignment of the Interface

Table 1-3
Pin No.
The housing of the RS485 interface is connected to the protective ground. We recommend using
standard connecting cables. The bus termination is accomplished via the connecting cable.
The isolated supply voltage of the interface is available at the D-Sub female connector, thus
allowing the data signal terminating resistors to be connected to the connecting cable.
Fig. 1-8 Termination of the RS485 interface (external)
Note
All computing devices connected to the RS485 interface port shall be connected to a SELV (Sep-
arated Extra Low Voltage) circuit and must comply with the following standard: IEC/EN 60950.
Power Meter SICAM P 7KG7750/55, Manual
E50417-B1076-C340-A6, Edition 09.2013
Terminal assignment of RS485 interface
Modbus / IEC 60870-5-103
1 Shield
2
3 A
4
5 GND
EXT
6 +5 V
EXT
7 RTS
8 B
9
RS485 Interface
Profibus DP
Shield
B(RxD/TxD-P)
GND
+5 V
CTRL-A
A(RxD/TxD-N)
+5 V
390 Ω
A
220 Ω
B
390 Ω
1
1.6 Interface and Terminals
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