Siemens 6ES7431-7KF00-0AB0 SIMATIC S7-400 SM 431 8AI 16-Bit U/I/Thermocouple Input Module

The Siemens 6ES7431-7KF00-0AB0 is a SIMATIC S7-400 SM 431 analog input module with 8 isolated channels for voltage, current, and thermocouple measurement at up to 16-bit resolution. It supports ten thermocouple types with internal or external cold-junction compensation, and it reports diagnostic and limit-value alarms plus a hardware interrupt back to the CPU whenever a reading leaves its parameterized range.

Technical Specifications

Selection Notes

Pick this SM 431 variant over the resistance-input sibling in the same family when the loop needs thermocouple inputs or 16-bit resolution, since this module trades resistance-input ranges for ten thermocouple types and a finer 16-bit conversion. The parameterizable diagnostic alarm and hardware interrupt let a broken sensor wire or an out-of-range reading trigger a CPU interrupt instead of waiting for a cyclic scan, which matters for temperature loops where a stuck reading can mask a real fault.

Applications

The mixed voltage, current, and thermocouple ranges on 8 isolated channels suit furnace, oven, and process-temperature monitoring on an S7-400 backplane, where several sensor types share one rack slot. The 10/16.7/20/100 ms conversion time is parameterizable per channel to trade speed for interference-frequency suppression at 50 Hz or 60 Hz.