The Siemens 3RK2402-2CG00-2AA2 is a Slimline Compact I/O module for AS-Interface, designated SC22.5, packing 4 digital inputs (PNP Type 2) and 4 relay outputs (NO contacts) into a 22.5 mm wide housing. It's an A/B slave per AS-i Spec. 3.0 with profile S-7.A.7 and a fixed ID1 code of 7. This is the module you spec when you need mixed I/O on an AS-i network without pulling a separate control cabinet bus — the relay outputs handle small motor starters, contactor coils, or signal lamps directly, while the PNP inputs accept standard 3-wire sensors.
Power supply and sensor feed — the practical split
The module draws 200 mA from the AS-i loop, or 500 mA when an auxiliary supply (Uaux) is connected. That extra 300 mA headroom matters when you're powering sensors from the module's own feed: the AS-i bus alone supplies up to 2 A for sensors, but if you need more than that or want to isolate sensor power from the network, you run a separate 20–30 V DC auxiliary feed and get up to 4 A for external loads. The relay outputs are rated 1 A at 24 V, 0.2 A at 110 V, 0.1 A at 230 V, with a thermal current of 5 A — so keep the switching loads within those limits, especially on inductive coils where inrush can exceed the steady-state rating.
Mounting and environment — panel fit
Screw and snap-on mounting on DIN rail, 22.5 mm wide, 100 mm high, 120 mm deep. IP20, so it lives inside a control cabinet — not on the machine frame. Shock rated at 15g / 11 ms for the module alone, 10g / 11 ms with the device connector attached. Accepts 0.5–1.5 mm² solid or stranded wire (20–16 AWG), 2- and 3-wire sensor connection. Address is set via the front facing socket, with yellow LEDs for I/O status.