Siemens 6ES7231-5PD32-0XB0 SIMATIC S7-1200 SM 1231 RTD 4AI Analog Input Module

The Siemens 6ES7231-5PD32-0XB0 is a SIMATIC S7-1200 SM 1231 RTD analog input module with 4 channels for resistance thermometers, supporting Pt, Ni, Cu, and LG-Ni sensor types across resistance ranges of 150, 300, or 600 Ω. Resolution reaches 15 bits plus sign, with a temperature error of ±0.1% of range at 25 °C.

Technical Specifications

Certifications & Standards

• CE mark
• CSA approval
• UL approval
• cULus
• FM approval
• RCM
• KC approval
• Marine approval

Selection Notes

Broad sensor-type support across Pt, Ni, Cu, and LG-Ni resistance thermometers means one module type can serve mixed sensor installations without stocking a separate RTD module per sensor family; the type is set per channel in software rather than by hardware jumper. The 15-bit-plus-sign resolution and 120 dB common-mode rejection at 50/60/400 Hz keep noise from AC power wiring out of the temperature reading, which matters when RTD leads run parallel to motor or drive cabling. Where thermocouple inputs are needed instead of resistance thermometers, a different SM 1231 variant in the same family is required — this module reads resistance-type sensors only.

Applications

Temperature monitoring for motor windings, bearing temperature, and process vessels using RTD sensors connected directly to an S7-1200 CPU without a separate signal conditioner.