Siemens SIMATIC ET 200AL System Manual page 1430

Wiring 2-wire transducers to an analog input for 4-wire transducers
The figure below shows an alternative to the above connection: supplying the 2-wire
transducer from supply line L+ of the module. If you use this type of connection, you will
need to set the "Current (4-wire transducer)" measurement type in STEP 7.
In this type of connection, galvanic isolation between the supply voltage L+ and the analog
circuit will be removed.
①
②
Figure 4-5
Wiring and connecting 4-wire transducers
4-wire transducers provide terminals for connecting a separate supply voltage. They are
powered with an external supply and are frequently called "active transducers". If you use
this type of connection, you will need to set the "Current (4-wire transducer)" measurement
type in STEP 7.
①
②
Figure 4-6
Analog value processing
Function Manual, 06/2014, A5E03461439-AC
2-wire transducers (2WT)
Equipotential bonding cable (only relevant to modules with M
Example: Wiring 2-wire transducers to an analog input for 4-wire transducers
4-wire transducers (4WT)
Equipotential bonding cable (only relevant to modules with M
Example: Wiring 4-wire transducers to an analog input module
Connecting transducers
4.5 Wiring current transducers
connection)
ANA
connection)
ANA
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