What this AS-i field module does
The Siemens 3RK2400-1GQ20-1AA3 is a K45 compact AS-Interface field module providing 4 digital input/output channels, each configured as 1 input and 1 output per M12 socket. It operates as an A/B slave per AS-i Specification 3.0, requiring a master that supports that revision. The module carries a maximum current of 1.5 A (derated to 2.5 A at 40 °C ambient), with built-in watchdog, short-circuit protection, and inductive load suppression — so the protection circuitry is onboard, not something you add externally.
Field deployment and wiring
Rated IP67, this module is built for direct mounting on machinery or in wet-area zones — washdown environments, not just dry cabinets. It mounts on standard DIN rail or to a wall via the optional K45 mounting plate (shipped without it). The four M12 sockets follow a fixed pinout: PIN 4 carries the data input (IN1–IN4), PIN 2 carries the output (OUT1–OUT4), PIN 1 is sensor supply L+, and PIN 3 is the common L- for both sensor supply and outputs. PIN 5 provides a ground terminal, routed out through a flat tab sleeve (2.8 x 0.8 mm form A). Input circuit is PNP transistor, so it expects sourcing sensors.
Status indicators and addressing
I/O status is indicated per channel via yellow LEDs; auxiliary power (Uaux) has a separate green LED. Addressing is done through a front-facing addressing socket — no DIP switches to mis-set. The ID/ID2 code is A/7, and the I/O configuration code is 7. Operating temperature range is -25 to +85 °C, storage -40 to +85 °C, with shock resistance rated at 15g for 11 ms.