Rs422/485 Interface Of The Communications Module - Siemens SIMATIC ET 200SP Equipment Manual

3.3

RS422/485 interface of the communications module

RS422/485 interface
The RS422/485 (X27) interface is a differential voltage interface for serial data transmission.
The inputs and outputs are not isolated from each other. The inputs and outputs are
electrically isolated from the backplane bus.
Terminal assignment of the BaseUnit
Table 3- 2 RS422/485 connection
Terminal assignment of
the
BaseUnit of the communi-
cations module
Front view
CM PtP communications module (6ES7137-6AA01-0BA0)
Equipment Manual, 03/2021, A5E03790792-01
Pin Designation
11 T (A)-
12 R (A)-
T(A)/R(A)
13 T (B)+
14 R (B)+
T(B)/R(B)
15 GND Ground
16
3.3 RS422/485 interface of the communications module
Input/output Meaning
Output Send data (four-wire mode)
Input Receive data (four-wire mode)
Input/output Receive/send data
(two-wire mode)
Output Send data (four-wire mode)
Input Receive data (four-wire mode)
Input/output Receive/send data
(two-wire mode)
--- Shared ground reference (ground)
Connecting
23