The Siemens 3SE3 120-0G is a position switch — a mechanical limit switch that detects the presence or absence of a moving part in a machine. It uses a roller crank actuator that can be rotated left or right, making it suitable for cam-operated or slide-mounted actuation on conveyors, packaging lines, and material-handling equipment. The IP67 protection class means the housing and actuator seal against dust ingress and temporary immersion — it survives washdown cycles on food-grade lines or outdoor conveyor sections without internal corrosion.
Integration notes
The M20 x 1.5 cable entry accepts standard metric gland fittings. The 40 x 38 x 130 mm body mounts via two M4 screws through the switch base — common DIN-rail adapter plates are available but the switch itself is a direct panel-mount unit. Roller crank actuators suit applications where the cam approaches from either direction; the rotary action reduces mechanical wear compared to plunger-type switches in high-cycle applications.