Siemens SIMATIC S7-1500 Manual page 14

Block diagram and pin assignment for voltage measurement
The example in the figure below shows the pin assignment for a voltage measurement.
①
②
③
④
Figure 3-2
Analog Input Module AI 8xU/I HS (6ES7531-7NF10-0AB0)
Manual, 07/2014, A5E03484886-AC
Analog-to-Digital Converter (ADC)
Backplane bus interface
Supply voltage via power supply element
Equipotential bonding cable (optional)
Block diagram and pin assignment for voltage measurement
Wiring
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