ASIsafe compact module for mechanical sensors
The Siemens 3RK1405-1BQ20-0AA3 is an ASIsafe compact module in the K45F form factor, carrying 2 safety-related digital inputs for mechanical switching contacts and 2 standard solid-state digital outputs powered from a separate 24 V DC auxiliary supply (Uaux). Rated IP67, the module survives washdown environments — the housing and M12 connectors seal against hose-directed water and dust ingress, making it suitable for food, beverage, or wet process lines where a safety-rated I/O drop is needed close to the hazard zone. Each safety input draws a minimum of 5 mA at the high signal level (contact closed) and reads the low level as contact open — designed for dry-contact mechanical switches or E-stops with no external pull-up resistor. The watchdog and short-circuit protection are built in, so no extra safety relay is required on the input side.
Mounts on standard DIN rail or to a wall using a separate mounting plate (3RK1901-2EA00 or 3RK1901-2DA00, ordered separately). The 15 mm wide, 80 mm tall, 34 mm deep footprint fits tight panel layouts alongside other K45 compact modules. Four M12 sockets handle I/O connections — inputs use special pin assignment for safety wiring, outputs follow standard assignment. Front addressing socket accepts AS-i bus master programmer. Status indication is via yellow LEDs per I/O point, a green LED for the auxiliary supply, and a combined green/red LED for AS-Interface bus and diagnostics. The AS-i protocol is supported natively, drawing up to 70 mA from the bus for its own electronics.
Electrical ratings and operating range
Operates on the AS-Interface bus voltage of 26.5 to 31.5 V DC per the AS-i specification. The standard outputs are rated at 2 A each, solid-state, short-circuit-proof, and require a separate 24 V DC auxiliary supply via the AUX POWER pins. The I/O configuration code is set to 7, with 4 I/O sockets on the module.