Siemens Simatic S7-300 - Isolation between the Bus Segments

RS 485 Repeater
7-5
Programmable Logic Controllers S7-300 Module Data
A5E00105505-03
Isolation between bus segments
Bus segment 1 and bus segment 2 are galvanically isolated from each other. The
PG/OP interface is connected internally to the port for bus segment 1. Figure 7-2
shows the front panel of the RS 485 repeater.
24 VDC
L+ M PE M 5.2
SIEMENS
RS 485-REPEATER
ON
A1 B1 A1 B1
A2 B2 A2 B2
PG
OP
DP2
OFF
ON
DP1
Terminals for bus segment 1
Terminals for bus segment 2
PG/OP
interface
Isolation
Figure 7-2 Isolation between the Bus Segments
Amplification of the bus signals
The amplification of the bus signals takes place between the port for bus segment
1 or the PG/OP interface and the port for bus segment 2.