Siemens 6ES7431-1KF00-0AB0 SIMATIC S7-400 SM 431 8AI 13-Bit U/I/R PLC I/O Module

The Siemens 6ES7431-1KF00-0AB0 SIMATIC S7-400 SM 431 module provides 8 isolated analog inputs at 13-bit resolution, measuring voltage, current, and 2/3/4-wire resistance up to 600 ohms on the same channels. Basic conversion time is 23 or 25 ms per channel, and basic error limit is within plus/minus 0.7 percent on voltage and current ranges at 25 degrees C. Channels are isolated from the backplane bus and from load voltage L+.

Technical Specifications

Selection Notes

Full isolation – between channels and the backplane bus, with internal/external separation – makes this module suited to analog signals from ungrounded or electrically noisy sources, where a shared-reference input would pick up common-mode noise. Four measurement types are supported on the same 8 channels: voltage, current, and 2/3/4-wire resistance up to 600 Ω, so one module can cover loop-powered 4-20 mA transmitters and resistive sensors without separate hardware. Basic conversion time is 23/25 ms per channel (50/60 Hz suppression), with 13-bit resolution and better than ±0.7% basic error on voltage and current ranges. Use the 4-wire resistance connection when line resistance must be excluded from the measurement.