Siemens 3SE2120-1B Push Button Selector Switch

Siemens 3SE2120-1B is a metal-enclosed limit switch in the 3SE family designed for end‑of‑travel and position sensing in industrial automation. It uses snap‑action contacts configured as 1 normally open (NO) and 1 normally closed (NC), enabling straightforward PLC wiring and control logic. Built for rugged factory environments, the 3SE2120-1B is commonly applied in conveyors, machine tools, and automated equipment where reliable switching at travel limits is essential. As a member of the 3SE2120 family, this model aligns with other variants such as 3SE2120-1C and 3SE2120-1G, illustrating a family approach to actuation and environmental compatibility, while the metal‑enclosed construction protects the internal mechanism for repeatable operation in demanding applications requiring dependable end‑stop sensing.