The Siemens 3SF7844-8MM50-0SS1 is a Type 4 safety light grid receiver from the SIMATIC FS420I family, operating as the receive half of a through-beam optoelectronic guard. It covers a protected height range of 300 mm to 900 mm with a sensing range of 0 to 18 m, and includes integrated muting for material-handling pass-through without tripping the safety output. Communication is over PROFIsafe via the FS420I bus interface, so it drops directly into a Siemens safety PLC architecture without a separate safety relay.
Deployment context
This receiver pairs with the matching Type 4 emitter to create a safety light curtain rated for finger and hand detection up to 900 mm of guarded height. The 18 m range covers long conveyor or gantry zones. Muting capability means it can be used on automated guided vehicle (AGV) transfer stations or palletizer infeed where material must pass through the field without stopping the machine — the muting sensors override the light grid during the material pass, then re-arm the safety function. The PROFIsafe bus connection eliminates a point-to-point safety relay, reducing panel wiring and simplifying SIL 3 / PL e certification documentation.