Safety switch with ASIsafe and positive opening — what ships in the box
The Siemens 3SF1244-1KC05-1BA2 is a SIRIUS mechanical safety switch in a compact block-style plastic housing (50 mm wide, 60.7 mm long) with screw fixing and any-position mounting. It carries one safety-related switching contact with positive opening (the NC contacts physically force the contacts apart, even if welded) and two auxiliary NC contacts — zero NO auxiliary contacts on this variant. The 24 V LED signals the AS-Interface bus status, and the ID1 code is set to F (hex, variable 0…F) for slave addressing. Rated for IP66/IP67, the enclosure handles washdown environments — suitable for food-and-bev or wet-area guard doors. The M12 plug, 4-pole, fixed connection uses pin 1 for ASI+, pin 3 for ASI-; pins 2 and 4 are unassigned.
ASIsafe loop-through and safety circuit integration
Safety-related communication runs over ASIsafe via the M12 plug, with channel 2 looped through to an M12 socket on the right side of the housing. This daisy-chain design means you don't break the ASI bus when you unplug the switch — the loop-through keeps the downstream devices online. The slave profile is 0.B.F. Slow-action contacts (not snap-action) and mechanical active principle with 15 million typical mechanical switching cycles. Repeat accuracy is 0.1 mm.