The Siemens SIRIUS 3SF1324-1SD21-1BK4 is a safety position switch with a tumbler locking force of 1 300 N — that's the force holding the guard closed against a determined push, not just a light detent. It's built for environments where washdowns are daily: IP66, IP67, and IP69 rated, so hot water and chemical sprays at high pressure won't get inside the plastic enclosure. The M12 plug carries ASIsafe communication, and the switch gives you five directions of actuator approach, which simplifies mounting alignment on a guard door or hatch.
Mounting position is any orientation, fixed with screws through the plastic housing. The M12 plug is fixed — pin 1 is ASI+, pin 3 is ASI-, and pins 2 and 4 are unassigned. The switch uses positive-opening contacts (2 NC for the actuator channel, 1 NC for the magnet channel per the 2v2 evaluation principle), so it meets the safety circuit requirements for a Category 4 or SIL 3 application when wired correctly. Repeat accuracy is 0.1 mm, which keeps the guard position consistent cycle after cycle over the rated 1 000 000 mechanical operations.