The Siemens 3RK1400-1MQ03-0AA4 is a single reversing motor starter in an IP67-rated housing, designed for 24 V DC control circuits. It packs four digital inputs (PNP) and one PNP transistor output, plus a built-in QuickStop function that can be wired to either of the two AS-Interface sockets for an emergency stop or safe-off signal.
IP67 means the housing is dust-tight and protected against temporary immersion — suitable for washdown zones on packaging or food-and-beverage lines where a standard panel-mount starter would need an extra enclosure. The 20 to 30 V DC supply range covers nominal 24 V systems with headroom for brownout conditions. The PNP input circuit is standard for most PLC and sensor families; the switching threshold is High ≥ 10 V, Low ≤ 5 V, so it works with 24 V logic without level shifting. The sensor supply on PIN 1 (L+) is short-circuit and overload protected, rated 200 mA at 40 °C and 150 mA at 55 °C — enough for a handful of proximity sensors or a small photoelectric eye, but not for a bank of valve solenoids.
This is a wall-mount module using the K60 mounting plate (sold separately — the module ships without it). The footprint is 60 mm wide × 152 mm high × 29 mm deep, so it fits in a small junction box or on a machine frame. Three AS-Interface sockets handle the I/O: socket 1 carries IN1 (D0/QuickStop1) and IN2 (D1); socket 2 carries IN3 (D2/QuickStop2) and IN4 (D3); socket 3 is the single PNP output (OUT1 on D0, D1).