AS-Interface I/O module for the control cabinet
The Siemens 3RK1402-3CE00-0AA2 is a SlimLine S22.5 AS-Interface I/O module designed for control-cabin mounting on 35 mm standard rail or directly to a panel wall using push-in lugs. It provides 4 digital inputs (PNP transistor, 20–30 V supply) and 4 relay changeover outputs, each rated for AC-15 duty at 3 A / 230 V — enough to switch small contactors, signal lamps, or solenoid valves without an interposing relay.
What the ratings mean for fit
The AC-15 rating of 3 A at 230 V / 50–60 Hz tells you the relay outputs are tested for inductive switching (typical for contactor coils and small motors), not just resistive loads. Each output is a floating changeover relay, so you can wire normally-open or normally-closed without external jumpers. The 4 inputs are PNP-sourcing, standard for Siemens and most European PLC families — verify your sensor common is 24 VDC, not 0 V. The module draws its power from the AS-Interface bus (20–30 VDC), and the built-in watchdog monitors communication. If the AS-i master stops talking, the outputs go to a safe state. The front addressing socket lets you set the slave address without pulling the module off the rail — useful when commissioning a line where every slot is already wired.
Mounting and wiring
At 45 mm wide and 106 mm tall, this module fits the SlimLine S22.5 footprint — one of the narrowest AS-i I/O slices on the market. The spring-cage terminals accept 1 x (0.5–4) mm² solid or 2 x (0.5–2.5) mm² stranded; with end sleeves, 1 x (0.5–2.5) mm² or 2 x (0.5–1.5) mm². An external 6 A gL/gG fuse protects each output group against short circuits. IP20 means it stays inside the cabinet — no washdown rating.