The Siemens SIRIUS 3SF1124-1LA00-1BA2 is a mechanical safety switch in a wide metal block housing, designed for positive opening of safety-related contacts — that means the NC contacts are mechanically forced open when the actuator is removed, even if the contacts are welded. This is the core requirement for a safety interlock per IEC 60947-5-1, and it carries one safety-related NC contact plus two auxiliary NC contacts, with no NO contacts on board. The 24 V DC LED indicator gives a quick visual on supply status at the switch body — useful during commissioning or fault-finding on a guarded gate. The switch communicates safety status over ASIsafe via a 4-pin M12 plug (pin 1 = ASI+, pin 3 = ASI-), with channel 2 looped through to an M12 socket on the right side for daisy-chaining. The AS-Interface slave profile is 0.B.F. Rated for IP66/IP67, the metal housing with cathodic dip coating handles washdown environments — think food processing, packaging lines, or outdoor conveyor gates where water and dust are constant. The screw-fixing method and any mounting position simplify panel integration, and the 56 mm width fits standard machine guarding frames.
The positive opening function is the deciding spec for safety circuits: it guarantees the NC contacts open mechanically when the guard is opened, regardless of weld or spring failure. That makes this switch suitable for safety-rated interlock applications up to SIL 3 / PL e when used with a compatible safety relay or ASIsafe master. Mechanical service life is rated at 15,000,000 operating cycles typical — that's well into the millions for a high-cycle gate or door interlock. Repeat accuracy of 0.1 mm means the switch position is consistent cycle-to-cycle, important for precise alignment in automated machinery. Surge voltage resistance is 0.8 kV, and insulation voltage is rated at 30 V. Shock resistance per IEC 60068-2-27 is 30g / 11 ms; vibration resistance per IEC 60068-2-6 is 0.35 mm / 5g. These figures confirm the switch holds up on vibrating machinery or near impact zones.