The Siemens 3SF7844-8BB11-0SS1 is a Type 4 safety light curtain receiver from the SIMATIC FS420I family, designed for guarding hazardous machinery with a 14 mm resolution and a 750 mm protected height. 14 mm resolution means it reliably detects individual fingers reaching into the hazard zone, meeting finger-protection requirements per IEC 61496-1. The 0 to 6 m operating range covers most machine-guarding layouts from compact cells to larger press lines.
Profisafe integration and deployment
This receiver communicates over a Profisafe bus connection to the SIMATIC FS420I safety controller, eliminating the need for a separate safety relay or hardwired OSSD outputs. The bus interface carries the safety signal directly into the F-CPU, which simplifies wiring in multi-zone guarding applications. Mounting hardware and alignment brackets are standard for the FS420I rail system; the receiver mates with its matching transmitter (order separately) to form a complete light curtain pair.