Wiring Non-Isolated Transducers - Siemens SIMATIC Manual

Wiring and connecting electrically isolated transducers to a non-isolated AI
The CPU / IM 153 can be operated in grounded mode or ungrounded mode.
Figure 4-2
Note
Do not interconnect M- with M
resistance transducers. An equalization current develops at the interconnection of M- with
M
ANA
programmed accordingly.
4.2.2

Wiring non-isolated transducers

Non-isolated transducer
Non-isolated transducers are interconnected with local ground potential. Always interconnect
M
ANA
Local conditions or interference may cause potential differences CMV (static or dynamic)
between locally distributed measuring points. If the maximum CMV value is exceeded,
interconnect the measuring points by means of equipotential conductors.
S7-300 Module data
Manual, 06/2017, A5E00105505-AJ
Wiring and connecting electrically isolated transducers to a non-isolated AI
and corrupts the measured value. This also applies to unused inputs which are
with local ground when using non-isolated transducers.
4.2 Wiring and connecting transducers to analog inputs
when wiring and connecting 2-wire transducers and
ANA
Principles of analog value processing
241