The Siemens 3RK1200-0CG02-0AA2 is an AS-Interface standard slave module from the SlimLine S22.5 family, designed for control-cabinet installation. It provides 4 digital inputs (PNP type) and no outputs, making it a pure input slice for an AS-i network. The module draws up to 270 mA from the AS-Interface bus, and critically requires a separate external auxiliary supply of 20 to 30 V DC for the output circuits — though since this unit has no outputs, that supply powers the input electronics and the AS-i interface itself. The auxiliary supply must comply with VDE 0106 (PELV), protection class III.
The slim profile means it fits in tight panel layouts where space is at a premium — a common constraint in retrofit or expansion work. IP20 rated, this is strictly for use inside a control cabinet. The spring-loaded terminals accept 2 x (0.25 - 1.5) mm² solid or stranded wire, or 2 x (0.25 - 1) mm² with end sleeves. A detachment tool is needed for release. Addressing is done via a front socket, with an ID/ID2 code of 0/F. The module supports 2- and 3-wire sensor technology, and the input switching level for a High signal is a minimum of 10 V.
For a BOM line requiring a 4-input AS-Interface standard slave, this module is a direct fit. The key ratings to confirm against your design are the 24 V DC auxiliary supply requirement and the 270 mA bus current budget.