Grounded/Non-Grounded Operation Of The Rs 485 Repeater; Et 200 Bus Segments Operating As Non-Grounded Segments; Top View Of The Rs 485 Repeater With Jumper - Siemens SIMATIC S5 Manual

RS 485 repeaters: installing, connecting and operating
6.5

Grounded/non-grounded operation of the RS 485 repeater

Grounded
operation
Non-grounded
operation
Installing RS 485
repeater for
non-grounded
operation
6-10
Grounded operation means that ground and PE are interconnected.
The RS 485 repeater is supplied with a jumper inserted between "M" and
"PE" (see Fig. 6-9). If the jumper is not inserted between "M" and "PE", you
must establish a conductive connection between "M" and "PE".
Non-grounded operation means that ground and PE are not connected.
If you use the RS 485 repeater in non-grounded mode, the bus segments can
operate with potential isolation.
The way in which the RS 485 repeater influences potential on bus segments
is illustrated in Fig. 6-8.
Signals non-grounded
Figure 6-8

ET 200 bus segments operating as non-grounded segments

To ensure non-grounded operation of the RS 485 repeater:
Remove the jumper in the power supply of the RS 485 repeater
and
ensure that the power supply to the RS 485 repeater is non-grounded.
Fig. 6-9 shows the RS 485 repeater from above with jumper inserted.
Figure 6-9

Top view of the RS 485 repeater with jumper

Signals grounded
Jumper
ET 200 Distributed I/O System
EWA 4NEB 780 6000-02a