The Siemens 6ES7231 PLC analogue I/O module has 4 integrated inputs with a signal range of (0)4 to 20mA. It is designed for use with SIMATIC S7-1200 series PLCs. It receives analogue input in the form of current or voltage. It has various advanced features like alarms and diagnostics that make it an ideal expansion module for various applications.
SIMATIC S7-1200, Analogue input, SM 1231, 4 analogue inputs, +/- 10 V; +/- 5 V; +/- 2.5 V; 0–20/4–20 mA, 12 bits + sign bit (13 bits ADC)