Siemens simatic hmi op27 Equipment Manual page 127

Electrical Installation
Configure interface The IF1B interface can be configured by using the DIL switches, located
IF1B beside the 9–pin Sub-D connector. This interchanges the RS422 receive data
and the RTS signal. By default, the RTS signal is not required by the commu-
nication peer.
The table shows the permissible DIL switch settings.
13-6
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
Communication
Communication
RS422/RS485
OP
PPI/MPI/PROFIBUS
OP
PPI/MPI
OP
Standard cable
Switch Setting
Switch Setting
PLC
1 2 3 4
1 2 3 4
RTS on Pin 4
1 2 3 4
RTS on Pin 9 (as PU)
PLC
1 2 3 4
No RTS on connector
(default)
PLC
1 2 3 4
OP27, OP37 Equipment Manual
Release 05/99
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
ON