Connecting Current Sensors - Siemens SIMATIC S7-400 Reference Manual

Analog modules

5.11 Connecting current sensors

5.11 Connecting current sensors
Sensor supply voltage
Note
The cables required to connect the analog input module and the sensors are not drawn in the
figures shown below.
In other words, you must continue to read and follow the instructions in the section "Connecting
sensors to analog inputs", which contains general information on connecting sensors.
The 2-wire sensor is wired to a short-circuit-proof supply voltage at the terminals of the analog
input module. This 2-wire transducer then converts the measured variable into a current.
Because the 2-wire transducer is supplied by the module, you must not ground the M- cables.
4-wire transducers require a separate supply voltage U
Connecting 2-wire transducers
1
Figure 5-8
M +:
M -:
L +:
M
ANA
(1)
(2) + (3)
(4)
208
2 3
P
P
Connecting 2-wire transducers to an isolated AI
Measuring line (positive)
Measuring line (negative)
Power supply connection 24 VDC
: Reference potential of the analog measuring circuit
Sensor, for example, pressure gauge
2-wire transducer
Connection required for modules with M
+24 V
L+
M+
+
M-
-
M+
+
M-
-
4
M
ANA
M
M
ana
Reference Manual, Ausgabe 11/2016, A5E00850736-08
(auxiliary supply).
H
S7-400 Automation System Module Data