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.
Panel fit and wiring
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.