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Entry type: FAQ Entry ID: 40913432, Entry date: 12/13/2012

How do you connect a sensor to the analog signal modules of SIMATIC S7-1200?

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Options for connecting a sensor to the analog signal modules of SIMATIC S7-1200.

A field sensor with the properties below can be connected to the analog input signal modules of S7-1200:

  • Measuring transducer with voltage output: +/-10 V, +/-5 V or +/-2.5 V or
  • 2-wire measuring transducer: 4-20 mA

The type of measurement (voltage or current) can be selected via 2 channels in each case.
The figures below show examples of how to connect different sensor types (voltage power supply: 24 V DC) to the analog signal module SM 1231 AI 4 x 13 Bit (channel 0):

Fig. 1: Potential-free voltage sensor (4-wire connection)

Fig. 2: Non-isolated voltage sensor with ground connection (3-wire connection)

Fig. 3: Current measurement via a 2-wire measuring transducer


  • When using a 4-20mA sensor, the measured value must be converted accordingly.
    Entry ID 39334504
  • Further information is available in the system manual for SIMATIC S7-1200. Entry ID: 36932465

Additional Keywords
2-wire, 3-wire, 4-wire

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