Siemens SIMATIC ET 200AL, System Manual

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Connecting transducers
4.5 Wiring current transducers
Analog value processing
72
Function Manual, 06/2014, A5E03461439-AC
4.5 Wiring current transducers
Current transducers are available as 2-wire transducers and 4-wire transducers. Below are a
number of ways to supply current transducers with voltage.
Wiring 2-wire transducers with power supply from the module
The 2-wire transducer converts the process variable into a current. The 2-wire transducer is
wired to the short circuit-proof supply voltage at the terminals of the analog input module.
The transducer is therefore frequently also called a "passive transducer". Its simple wiring
means that the 2-wire transducer is frequently used in industrial environments. If you use this
type of connection, you will need to set the "Current (2-wire transducer)" measurement type
in STEP 7.
Note
2-wire transducers must be electrically isolated.
①
2-wire transducers (2WT)
②
Equipotential bonding cable (only relevant to modules with M
ANA
connection)
Figure 4-4 Example: Wiring 2-wire transducers to an analog input module