The Siemens 3SF3100-0DV00-0BA2 is a communication-capable position switch with an integrated AS-i adapter, built for direct connection to an AS-interface network without a separate I/O module. The roller plunger actuator gives a positive-opening NC contact — that means the NC is mechanically forced open when the plunger is depressed, which is the safety-relevant switching function you want for guard-door monitoring or end-of-travel interlocking. The metal enclosure and IP65 rating let it live on a machine frame or conveyor section where washdown or dust is present; the block housing follows EN 50041, so it shares the standard mounting footprint with other limit switches in that form factor.
The single NC contact (no NO) is deliberate — this is a safety-position feedback switch, not a dual-channel selector. The positive-opening mechanism (per IEC 60947-5-1) guarantees the NC breaks even if the contacts weld, which is what a safety PLC or safety relay expects on its input. The AS-i connection uses the insulation displacement method: strip the round cable, push it into the slot, no screw terminals. That saves wiring time on a multi-drop AS-i line but means you need the correct AS-i profile cable (2-wire, flat or round). The roller plunger is a standard choice for cam-actuated or sliding-door applications; the roller reduces wear on the actuator surface compared to a straight plunger.