The Siemens 3RK2400-1BQ30-0AA3 is a K20 field I/O module for AS-Interface networks, configured as an A/B slave with 2 digital inputs and 2 digital outputs. It's built for distributed I/O in the field, meaning it sits on the machine frame or conveyor line rather than in a central cabinet — the IP67 rating confirms it withstands washdown and airborne particulates in production environments.
Each output channel is rated 1 A maximum, which governs the solenoid valves, signal lamps, or small contactor coils this module can drive directly. The input circuit uses PNP transistor technology, so it expects sourcing sensors (e.g., 3-wire proximity switches) that pull the input high when active. The module requires an external auxiliary supply of 20 to 30 V DC for the output circuits, separate from the AS-Interface bus power. That supply must comply with VDE 0106 (PELV) protection class III — a standard requirement for touch-safe low-voltage circuits in industrial control panels. Built-in short-circuit protection and induction suppression mean the module handles typical field-wiring faults without external clamp diodes or fuses per channel. The watchdog timer resets outputs if the AS-Interface master communication drops, which is standard for safety-related distributed I/O architectures.
The housing is 20 mm wide, 108 mm tall, and 45 mm deep — no mounting plate required, so it clips directly onto a DIN rail or mounts via the integrated screw holes. Two M12 I/O sockets handle the field wiring; addressing is set through the M12 female connector rather than DIP switches, which simplifies configuration but means the addressing cable must be on hand during commissioning. Shock resistance of 15 g for 11 ms means it survives typical machine vibration and handling during transport. The yellow LEDs indicate I/O state per channel; the green LED confirms the auxiliary supply is present.