The Siemens 3RK1400-1BQ20-0AA3 is a K45 compact field digital I/O module — 2 PNP inputs and 2 PNP outputs, each output rated for up to 3 A with built-in short-circuit and induction protection. The IP67 rating means the whole module, including the M12 sockets, handles washdown environments without an extra enclosure — useful on conveyors, packaging lines, or any spot where you'd rather run the I/O out to the sensor than pull every wire back to a cabinet.
Power and wiring gotcha
One detail that trips up a first fit: the outputs need their own external AUX POWER supply at 20 to 30 V DC, separate from the sensor supply on PIN 1. That AUX supply must comply with VDE 0106 (PELV), protection class III. The module's own input voltage is the same 20 to 30 V DC range, fed through the M12 connector. PIN 5 on each socket is the ground terminal, routed out via a flat tab sleeve (2.8 x 0.8 mm form A). Yellow LEDs on each I/O channel show state; a green LED confirms the AUX supply is present.