What this module does
The Siemens 6ES7144-1JB31-0XB0 is an RTD input module with two analog inputs, wired through 4/5-pin M12 circular connectors, accepting Pt100 resistance thermometers with channel-by-channel wire-break detection and diagnosable alarms.
Module width is 60 mm on the backplane (overall housing 87 mm), depth 55 mm, height 110 mm. M12 connectors keep the gland plate clean — shielded runs up to 30 m. Two-wire, three-wire, and four-wire Pt100 connections are supported with a 10 MΩ input resistance that doesn't load the sensor. Supply draw from L+ is 40 mA max; the module dissipates 0.9 W typical — negligible for the bus coupler budget but worth noting if you're stacking a dozen of these on a segment.
Diagnostics and accuracy
Diagnostic alarm, limit value alarm (upper/lower, channel-selectable), hardware interrupt, and overflow/underflow detection are all present and parameterizable. Group error SF (red) LED gives a visual heads-up on the module face. Common-mode rejection is at least 60 dB, crosstalk between inputs stays below -45 dB, and linearity error holds within ±0.05 % of the input range. Resolution is 12 bits plus sign, with overrange to 17.5 %. Temperature drift is ±0.01 %/K of input range; overall accuracy for resistance measurement with Pt100 is ±1.2 % of input range — consistent with a clean industrial-grade RTD input that doesn't need constant re-calibration.