Appendix
136/142
netPLC C100 | Startup Guide
DOC090701UM02EN | Revision 2 | English | 2009-10 | Released | Public
© Hilscher, 2009
18.5 PROFIBUS Interface
18.5.1
PROFIBUS Interface Pinning
Isolated RS-485 interface:
Figure 15: PROFIBUS Interface (DSub female connector, 9 pin), X400
Connection with
DSub female
connector
Signal Meaning
3
RxD/TxD-P
Receive / Send Data-P respectively
connection B plug
5 DGND
Reference
potential
6
VP
Positive power supply
8
RxD/TxD-N Receive / Send Data-N respectively
connection A plug
Table 33: PROFIBUS Interface, X400
18.5.2
PROFIBUS Wiring
Please ensure that termination resistors are available at both ends of the
cable. If special PROFIBUS connectors are being used, these resistors are
often found inside the connector and must be switched on. For baud rates
above 1.5 MBaud use only special connectors, which also include
additional inductance.
It is not permitted to have Tstubs on PROFIBUS high baud rates. Use only
a special cable which is approved for PROFIBUS DP. Make a solid
connection from the cable shield to ground at every device and make sure
that there is no potential difference between the grounds at the devices.
If the slot PLC is linked with only one other device on the bus, they must be
at the ends of the bus line. The reason is that these devices must deliver
the power supply for the termination resistors. Otherwise the Master can be
connected at any desired position.
