Siemens Digital I/O Module AS-I K20 Digital

This digital I/O module provides compact, field-mountable input and output interfacing for AS‑Interface networks in harsh environments. Designed for direct connection to sensors and actuators, it supports bidirectional digital signalling and fits into distributed automation installations where a sealed, rugged I/O device is required.

• Four inputs with PNP switching deliver reliable sensor detection at DC voltages
• Four PNP transistor outputs supply up to 1A per channel for actuator control
• Aggregate output limit 2A ensures protected total load handling
• Sensor supply short‑circuit and overload resistant for fault tolerance
• Built to IP67 for dust-tight and waterproof operation in exposed locations
• Eight M8 sockets with M12 addressing connector simplify field wiring

• Suitable for decentralised actuator control on AS‑Interface networks
• Ideal for machine I/O in washdown or outdoor installations
• Used for signal collection from 2‑ and 3‑wire proximity sensors
• Can be used for Compact conveyor control with multiple outputs

The device operates from the AS‑Interface supply within 26.5 to 31.6 V and accepts input voltages to the sensor supply of 16.5 to 30 V.

Each socket’s PIN4 carries the data line with sockets 1–4 mapped to four inputs and sockets 5–8 mapped to four outputs per the supplied pin assignment.

Yes, an auxiliary 20–30 V DC supply is necessary to feed the output circuits and must meet protection class III requirements.

The module includes multi‑colour LEDs for AS‑Interface/diagnostics, separate LEDs for I/O status, and an LED indicating the auxiliary supply presence.