The Siemens 3SF3120-6DV00-0BA1 is a communication-capable position switch with an integrated AS-i adapter, designed for direct connection to an AS-interface network without a separate I/O block. The mechanical roller plunger actuator (design C per EN 50041) provides positive opening of the 2 NC contacts — meaning the normally-closed circuit is mechanically forced open when the plunger is depressed, even if the contacts weld. That positive opening feature is the safety-relevant detail here: it meets the requirements for a safety-related position interlock in a guard door or transfer station.
The block-style housing conforms to EN 50041, a common footprint for limit switches in European machinery; it mounts via screw fixing and accepts the standard 40 mm width. The AS-i connection uses the insulation displacement method, so wiring is a simple push-down onto the flat cable — no screw terminals, no separate AS-i module needed.