The Siemens 3SF3120-6GW00-0BA1 is a communication-capable position switch with an integrated AS-i (Actuator-Sensor Interface) adapter, designed for direct connection to an AS-i network without a separate interface module. It uses a mechanical active principle with a twist lever actuator and a positive opening switching function — meaning the NC contacts are mechanically forced open when the actuator is released, regardless of weld or spring failure, which is the safety-relevant requirement for guard door monitoring per IEC 60947-5-1. The housing is a metal block design conforming to EN 50041, painted, with screw fixing. It carries 2 NC contacts and 0 NO contacts, so it is a normally-closed-only configuration — typical for safety circuits where the switch interrupts the safety chain on door opening and relies on redundancy through two NC channels.
IP65 and deployment context
Connection is via AS-i insulation displacement method — the flat cable pierces into the AS-i bus without stripping or separate terminals, which speeds installation on long bus runs. The twist lever actuator (design A per EN 50041) gives a defined roller-crank motion; the 10° to 10° grd (ground) angle in the description suggests a slow-action roller crank that actuates over a small angular travel, suitable for cam-operated guard positions.