The Siemens 3SF1124-1KA00-1BA2 is a SIRIUS mechanical safety switch with a positive-opening contact set — the kind you spec into a guard-door interlock or a hinged access panel where you need a hard-wired, non-defeatable break in the safety circuit. It carries one safety-related NC contact and two auxiliary NC contacts, all slow-action, so the switching state is predictable at low speeds. The housing is metal with a cathodic dip coating, rated IP66/IP67, which means it handles washdown environments and outdoor exposure without the housing corroding through. Communication goes over AS-Interface via a 4-pin M12 plug — Pin 1 is ASI+, Pin 3 is ASI-, and the safety signal travels on channel 2, looped through to an M12 socket on the right side of the switch. The AS-Interface slave profile is 0.B.F, and the ID1 code is set to F (hex, variable 0...F). That means the switch presents itself as a standard safety slave on the AS-i bus; no special gateway configuration needed beyond assigning the address. The optional LED indicator runs on 24 V DC, which is handy for a quick visual check that the switch is powered without needing to meter the AS-i line. The switch itself is mechanical — no electronics in the safety path — so the mean time to dangerous failure is driven by the contacts, not a semiconductor junction.
Mounting position is any orientation, secured by screw fixing through the 56 mm wide metal block housing. The sensor length is 99.7 mm. Shock resistance is 30 g for 11 ms per IEC 60068-2-27, and vibration resistance is 0.35 mm / 5 g per IEC 60068-2-6. That covers most machine-mounted applications without needing a separate vibration isolator. The surge voltage resistance is 0.8 kV, and insulation voltage is rated at 30 V — keep that in mind if the AS-i line runs near higher-voltage power cables in the same trunk.