What it is and what it does
The Siemens 3RK1405-1BE00-0AA2 is an ASIsafe SlimLine safety I/O module from the SIRIUS family, designed to bring safe digital inputs and standard outputs onto an AS-Interface safety network. It provides 2 safety-related digital inputs rated for mechanical switching contacts and 2 standard solid-state outputs, each powered from the 24 V DC AUX supply. The module communicates over the AS-Interface bus, drawing up to 60 mA from the bus for its own electronics.
What the ratings mean for fit
The 22.5 mm housing (S22.5F) is the SlimLine footprint — it snaps onto a standard 35 mm DIN rail and saves panel width compared to the wider 45 mm safety relay blocks. The 91 mm depth fits standard 100 mm deep enclosures with room for wiring behind the module. The AS-Interface operating voltage range of 26.5 to 31.5 V DC matches the standard AS-i power supply output; the module also requires a separate 24 V DC AUX supply to power the two solid-state outputs. The built-in watchdog, short-circuit protection, and induction protection mean the module handles its own fault monitoring and output protection without external fusing or suppression diodes.
Panel integration and wiring
Mounts on a 35 mm DIN rail or directly to a panel backplate via the standard rail mounting or wall mounting slots. The screw terminals accept the AS-i bus cable and the 24 V DC AUX supply wiring. The front addressing socket lets you set the AS-i slave address without removing the module. The yellow LEDs indicate I/O state per channel; the green/red LED shows AS-Interface communication and diagnostics. The ID/ID2 code B/F is factory-set and identifies the module profile to the AS-i master.
Environmental limits
Rated for operation from -25 to +70 °C and storage from -40 to +85 °C, which covers most control cabinet environments including unheated warehouses. The IP20 protection class means it is suitable for dry indoor panels only — no washdown or outdoor exposure without an additional enclosure.