Siemens SINAMICS G150 Operating Instructions Manual page 346

Operation
6.8 Communication via PROFIBUS DP
PROFIBUS connection
The PROFIBUS is connected by means of a 9-pin SUB D socket (X126). The connections
are electrically isolated.
Table 6- 27 X126 - PROFIBUS connection
Pin Signal name
1 SHIELD
2 M24_SERV
3 RxD/TxD-P
4 CNTR-P
5 DGND
6 VP
7 P24_SERV
8 RxD/TxD-N
9 -
Connectors
The cables must be connected via PROFIBUS connectors as they contain the necessary
terminating resistors.
The figure below shows suitable PROFIBUS connectors with/without a PG/PC connector.
Bus terminating resistor
The bus terminating resistor must be switched on or off depending on its position in the bus,
otherwise the data will not be transmitted properly.
The terminating resistors for the first and last nodes in a line must be switched on; the
resistors must be switched off at all other connectors.
346
Meaning
Ground connection
Power supply for teleservice, ground
Receive / transmit data P (B/B')
Control signal
PROFIBUS data reference potential (C/C')
Supply voltage plus
Power supply for teleservice P, + (24 V)
Receive / transmit data N (A/A')
Not assigned
PROFIBUS connector
without PG/PC connection
6ES7972-0BA42-0XA0
Range
0 V
RS485
TTL
5 V ± 10%
24 V (20.4 ... 28.8 V)
RS485
PROFIBUS connector
with PG/PC connection
6ES7972-0BB42-0XA0
Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A