Connecting; Connecting Measuring Sensors - Siemens SIMATIC ET 200S Manual

Connecting

5.1

Connecting measuring sensors

Introduction
You can connect a current sensor in the form of a 2-wire transducer to the 2AI I 2WIRE HS
analog input module.
In this chapter you will find out how to connect the measuring sensors and what to watch for
when doing so.
Lines for analog signals
You should use shielded and twisted-pair lines for the analog signals. This reduces the effect
of interference. You should ground the shield of the analog lines at both ends. If there are
differences in potential between the line ends, an equipotential bonding current that may
interfere with the analog signals will flow across the shield. In this case, you should only
ground the shield at one end of the line.
Analog input modules
In the case of the analog input modules there is electrical isolation:
● Between channels and backplane bus
● Between load voltage and the channels
Connection of measuring sensors to analog inputs
Between the measuring circuits M- of the input channels and the reference point of the
measuring circuit M
voltage). To ensure that the permitted value is not exceeded, you must take different steps
depending on the whether the sensors are isolated or non-isolated. The steps you have to
take are described in this section.
Generally speaking, however, when connecting 2-wire transducers for current measurement,
you should not make a connection from M- to M
also applies to inputs that have been assigned accordingly but are not used.
2AI I 2WIRE HS analog electronic module (6ES7134-4GB52-0AB0)
Manual, 01/2008, A5E01001734-02
, there can be only a limited potential difference U
ANA
, from M+ to M , or from M+ to M-. This
ANA ANA
5
(common-mode
CM
23