The Siemens 3RK2400-1FE00-0AA2 is an AS-Interface SlimLine S22.5 I/O module designed for control-cabinet mounting. It gives you 4 digital inputs (PNP, 24 V switching level) and 3 solid-state outputs in a single 45 mm wide housing that snaps onto 35 mm standard rail or mounts to a wall panel with push-in lugs. The 4 inputs are addressed as D0 (IN1/OUT1), D1 (IN2/OUT2), D2 (IN3/OUT3), and D3 (IN4). The 3 outputs share the first three data bits, so the module uses I/O configuration code 7. It operates as an A/B slave, which means it can sit on the same AS-i cable as standard slaves without address conflicts.
Power and wiring constraints
This module pulls its logic power from the AS-Interface cable, but the output circuits need a separate auxiliary supply — 20 to 30 V DC, PELV per VDE 0106, protection class III. That external AUX POWER rail is mandatory; without it the outputs won't fire. The input voltage range is 20 to 30 V DC, and the aggregate current across all outputs is capped at 4 A. Terminals accept 1 x (0.5 - 4) mm² or 2 x (0.5 - 2.5) mm² solid, or with end sleeves 1 x (0.5 - 2.5) mm² or 2 x (0.5 - 1.5) mm². AWG equivalent is 2 x (20 - 14). The module has built-in short-circuit protection and induction protection, plus a watchdog that resets outputs if the AS-i master stops communicating.
Status at a glance
Three LED banks tell you what's happening: green for AS-Interface communication, yellow per I/O channel for signal state, and red for fault. The addressing socket is on the front — you plug in an AS-i hand-held programmer or addressing unit to set the slave address. The factory default ID/ID2 code is A/0.