The Siemens 3RK1207-3CG00-2AA2 is an AS-Interface Slimline Compact I/O module designed for control-cabinet use. It provides four analog inputs with 16-bit A/D resolution, configurable for Pt100/Ni100 RTDs, resistance up to 600 Ω, or standard voltage/current signals. The module is a standard AS-i slave with profile S-7.3.E and draws its main power from the AS-i bus, but requires a separate 20–30 VDC auxiliary feed (PELV per IEC 60990, protection class III) to power the output circuits — an easy miss during panel design if you expect self-powered operation.
The 22.5 mm width fits standard Slimline spacing on DIN rail, with screw and snap-on mounting for quick install or swap without removing adjacent modules. The analog inputs accept Pt100 standard and climate range, Ni100, or 0–600 Ω resistance measurement, plus voltage/current signals — so it handles RTD temperature probes directly without an external transmitter. The 16-bit resolution gives you roughly 0.01 °C per count on a Pt100, which is fine for process monitoring but not precision metrology. Input variable parameterization is supported, meaning the range and type are set via the AS-i master, not DIP switches on the side. Operating voltage follows the AS-Interface spec at 18–31.6 VDC, and the module draws up to 100 mA from the bus at 24 V with AS-i Power24V. The auxiliary feed for output circuits can supply up to 4 A — plan for that in your 24 VDC distribution. Storage temperature range of -40 to +85 °C and operating range of -25 to +70 °C cover most industrial environments, but shock resistance of 15g/11 ms (10g with connector) means it's not rated for high-vibration machinery without additional dampening.