Siemens SIMATIC ET 200S Manual page 21

Non-isolated measuring encoders
The non-isolated measuring encoders are connected to the local ground potential. You must
connect M
potential differences U
measuring points.
If the permitted value for U
between the measuring points.
The following schematic representation illustrates the connection of non-isolated measuring
encoders to an optically isolated analog input module.
Connection of non-isolated measuring encoders to an optically isolated analog input module:
5
4
①
②
③
④
⑤
Operating four-wire transmitters on an external voltage supply
If there is electrical isolation between the output and the transmitter supply, you can connect
the transmitter to the 2 AI I 4WIRE ST without the need for additional connections.
If there is no electrical isolation between the output and the transmitter supply, you can only
connect the transmitter to the 2 AI I 4WIRE ST if the reference potential of the supply
voltages (24 V DC) is the same.
If there is an increase in interference radiation, it is recommended that you connect M- to
M
ANA
2AI I 4WIRE ST analog electronic module (6ES7134-4GB11-0AB0)
Manual, 04/2007, A5E01076100-01
to the ground potential. Depending on local conditions or interference,
ANA
(static or dynamic) can occur between the locally distributed
CM
CM
Logic
Backplane bus
Ground bus
Equipotential bonding conductor
Non-isolated measuring encoders
on the terminal module of the 2 AI I 4WIRE ST.
is exceeded, there must be equipotential bonding conductors
3
5.1 Connecting measuring sensors
1
2
Connecting
21