The Siemens 3SF3120-8GW00-0BA1 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. Its mechanical active principle and positive opening switching function (EN 60947-5-1) mean the NC contacts are forced open by the actuator — a requirement for safety-related stop circuits where the switch must break the circuit even if contacts weld. The twist lever actuator (10° to 10° operating angle) suits cam-actuated or sliding-door positions on packaging machines, conveyors, or transfer lines.
The metal block housing (EN 50041 design A) is painted and screw-fixed, giving it the mechanical robustness for high-cycle applications on machine tools or heavy automation. Two normally-closed (NC) auxiliary contacts (no NO contacts) make this switch a dedicated safety input: it signals the safety PLC or AS-i safety monitor when the guard is open, and the positive opening mechanism guarantees the signal even under contact weld.
AS-i connection and wiring
The electrical connection uses AS-i insulation displacement method — the switch pierces the AS-i flat cable directly, no separate tee or junction needed. This simplifies daisy-chaining multiple switches along a line; just lay the AS-i cable through the housing and clamp. Screw fixing to the machine frame or bracket is standard; the housing profile matches EN 50041 block dimensions, so it drops into existing cutouts or brackets designed for that standard.