Siemens SINAMICS S150 Operating Instructions Manual page 201

PROFIBUS link
The PROFIBUS link is connected by means of a 9-pin SUB D socket (X126). The
connections are electrically isolated.
Table 6-7 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.
Principle: the terminating resistors must only be switched on at both ends of the bus line; the
resistors must be switched off at all other connectors.
The cable shield must be connected at both ends over large-surface area contacts.
Drive converter cabinet units
Operating Instructions, 07/07, A5E00288214A
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
6ES7972-0BA41-0XA0
6.6 PROFIBUS
Range
0 V
RS485
TTL
5 V ± 10 %
24 V (20.4 V - 28.8 V)
RS485
PROFIBUS connector
with PG/PC connection
6ES7972-0BB41-0XA0
Operation
201