The Siemens 3SF7844-8BD04-1SS1 is a Type 4 safety light curtain host receiver from the SIMATIC FS420I family, with 30 mm resolution, 300 mm blanking capability, and a detection range of 0 to 18 meters. It connects via PROFIsafe bus, making it a direct fit for Siemens safety-rated automation cells where the controller expects a PROFIsafe safety drive or F-CPU. Type 4 per IEC 61496-1 means it can be used for finger and hand protection in high-risk guarding applications — the 30 mm resolution catches fingers reaching into the hazard zone, while the 18 m range covers longer access points on a conveyor or machine perimeter.
Deployment Context
This host receiver is the PROFIsafe bus-connected half of a Type 4 light curtain pair — it handles the safety logic communication back to the F-CPU or safety drive, so the emitter (ordered separately) completes the pair. The 300 mm blanking feature lets you program fixed or floating blanking zones to ignore small objects (like a part on a conveyor) without disabling the entire curtain. Mounting hardware and alignment aids are standard for the FS420I family; the PROFIsafe connection uses a standard M12 bus connector, which keeps field wiring consistent with the rest of a Siemens safety network.