Operating instructions

Operation
6.6 PROFIBUS
Drive converter cabinet units
Operating Instructions, 10/2008, A5E00288214A
211
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 Meaning Range
1 SHIELD Ground connection
2 M24_SERV Power supply for teleservice, ground 0 V
3 RxD/TxD-P Receive / transmit data P (B/B') RS485
4 CNTR-P Control signal TTL
5 DGND PROFIBUS data reference potential (C/C')
6 VP Supply voltage plus 5 V ± 10 %
7 P24_SERV Power supply for teleservice P, + (24 V) 24 V (20.4 V - 28.8 V)
8 RxD/TxD-N Receive / transmit data N (A/A') RS485
9 - not assigned
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.
PROFIBUS connector
without PG/PC connection
6ES7972-0BA41-0XA0
PROFIBUS connector
with PG/PC connection
6ES7972-0BB41-0XA0
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.