Siemens SIMATIC ET 200MP Manual page 18

Connection: 2-wire and 3-wire connection of resistance sensors or resistance thermometers (RTD)
The example in the following figure shows the pin assignment for 2-wire and 3-wire
connections of resistance sensors or resistance thermometers.
①
3-wire connection
②
2-wire connection
③
Analog-to-digital converter (ADC)
④
Backplane bus interface
⑤
Infeed element (for shielding only)
Figure 3-5 Block diagram and pin assignment for 2-wire, 3-wire connection
Analog Input Module AI 8xU/I/R/RTD BA (6ES7531-7QF00-0AB0)
Manual, 03/2019, A5E44792324-AA
CHx Channel or 8 x channel status (green/red)
RUN Status display LED (green)
ERROR Error display LED (red)
Wiring
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