Siemens simatic s7-1500 User Manual page 20

Wiring
Block diagram and pin assignment for voltage measurement
The example in the following figure shows the pin assignment for voltage measurement.
①
Analog-to-Digital Converter (ADC)
②
Electrical isolation
③
Backplane bus interface
④
Supply voltage via power supply element
⑤
Equipotential bonding cable (optional)
Figure 3-2 Block diagram and pin assignment for voltage measurement
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CHx Channel or 9 x channel status (green/red)
RUN Status display LED (green)
ERROR Error display LED (red)
PWR LED for power supply (green)
Analog Input Module AI 8xU/R/RTD/TC HF (6ES7531-7PF00-0AB0)
Manual, 09/2016, A5E36647959-AB