Siemens SIMATIC S7-400 Reference Manual page 234

Analog modules
5.19 Analog input module SM 431; AI 8 x 13 Bit (6ES7431-1KF00-0AB0)
● For voltage measurement
● For current measurement
● For resistance measurement
234
– As 2-wire transducer
– As 4-wire transducer
– With 2-wire connection
– With 3-wire connection
– With 4-wire connection
Possible
Possible; with external measuring transducer
supply
Possible
Possible; line resistance is also measured
Possible
S7-400 Automation System Module Data
Reference Manual, Ausgabe 11/2016, A5E00850736-08