Siemens SIMATIC User Manual

Principles of analog value processing
4.2 Wiring and connecting transducers to analog inputs
S7-300 Module data
240 Manual, 06/2017, A5E00105505-AJ
4.2.1 Wiring and connecting electrically isolated transducers
Electrically isolated transducers
Electrically isolated transducers are not connected to local ground potential. They can be
operated in electrically isolated mode.
Potential differences may develop between electrically isolated sensors. These potential
differences may be caused by interference, or may develop as a result of the local
distribution of transducers.
In environments with a high level of EMC interference, it is advisable to interconnect M- with
M
ANA
in order to prevent the permissible CMV value from being exceeded.
Note
For modules where V
CM
≤ 2.5 V, interconnect M- and M
ANA
(see the diagrams below).
Wiring and connecting electrically isolated transducesr to an electrically isolated AI
The CPU / IM 153 can be operated in grounded mode or ungrounded mode.
Figure 4-1 Wiring and connecting electrically isolated transducers to electrically isolated AI

Siemens SIMATIC Specifications

General

Brand	Siemens
Model	SIMATIC
Category	Control Unit
Language	English