Safety switch with tumbler locking and ASIsafe integration
The Siemens SIRIUS 3SF1324-1SG21-1BA4 is a mechanical safety switch with a tumbler locking mechanism rated at 1300 N locking force, designed for guard-door monitoring in safety circuits up to PL d / SIL 3 when wired per the 2v2 evaluation principle. The spring-actuated lock follows the closed-circuit principle — power to the magnet holds the lock open; spring force closes it on power loss, so a fault or cable break puts the guard in the safe state. Escape release from the rear and auxiliary release from the front let an operator open the guard from inside or a technician override it without tools.
AS-Interface integration and wiring
The switch integrates directly onto an AS-Interface safety network via the fixed M12 plug. Pinout is standard: Pin 1 = ASI+, Pin 3 = ASI-. The AS-Interface slave profile is 7.B.F, which the safety monitor recognizes for the dual-channel evaluation. Channel 1 monitors the actuator (2 NC contacts per the positive-opening principle), and channel 2 monitors the magnet (1 NC contact) — this gives the safety PLC or ASI monitor two independent feedback paths so a single fault does not defeat the safety function. The ID1 code is set to F by default, configurable 0...F for addressing on multi-switch lines.
Deployment context
Mounts in any position via screw fixing to the machine frame or guard-door profile. The plastic housing with special design and 5 directions of approach give flexibility for tight spaces. Vibration resistance to 0.35 mm / 5g and shock resistance to 30g / 11 ms mean it holds up on press brakes, punch presses, and conveyor transfer stations without nuisance trips.