Siemens Simatic M7-400 Reference Manual page 423

10.2 Appearance of the RS 485 Repeater;
(6ES7972-0AA01-0XA0)
The table below shows the appearance of the RS 485 repeater and lists its
functions.
Table 10-3 Description and Functions of the RS 485 Repeater
Repeater Design
24 VDC
L+ M PE M 5.2
10 10
A1 B1 A1 B1 A1 B1 A1 B1
ON
DP1
È
PG
OFF
OP OP
DP2
ON
SIEMENS SIEMENS
RS 485-REPEATER
A2 B2 A2 B2
S7-400, M7-400 Programmable Controllers Module Specifications
A5E00069467-07
No
.
À
Connection for the RS 485 repeater power supply (pin "M5.2" is
the ground reference, if you want to measure the voltage
difference between terminals "A2" and "B2").
À À
Á
Shield clamp for the strain relief and grounding of the bus cable
Á
of bus segment 1 or bus segment 2
Â
Terminals for the bus cable of bus segment 1
 Â
Ã
Terminating resistance for bus segment 1
Ä
Switch for OFF operating mode
Ã
(= isolate bus segments from each other – for example, for
11
Ä
startup
12 12
Å
Å
Terminating resistance for bus segment 2
Æ
Terminals for the bus cable of bus segment 2
Ç
Slide for mounting and removing the RS 485 repeater on the
Æ
standard rail
È
Interface for programming device/OP in bus segment 1
Á Á
LED 24 V supply voltage
10
Ç
LED for bus segment 1
11
LED for bus segment 2
12
RS 485 Repeater
Function
10-3