Safety light curtain Type 4 host receiver
The Siemens 3SF7844-8BB15-1SS1 is a Type 4 safety light curtain host receiver from the SIMATIC FS420I series, with 14 mm resolution and a 1050 mm protected height. The 14 mm detection capability means it catches fingers reaching into the hazard zone — finger-protection class per IEC 61496-1. Operating range is 0 to 6 m, and it connects via PROFIsafe bus for direct integration into a safety-rated fieldbus network.
Deployment context
As a Type 4 safety light curtain, this receiver is intended for guarding hazard zones on machinery — presses, robots, assembly lines — where a person reaching into the danger area must be reliably detected. The PROFIsafe bus connection eliminates separate safety relay wiring; the safety signal travels over the same cable as standard PROFINET traffic, simplifying panel layout and reducing terminal count.