Safety light curtain, Type 4 host receiver
The Siemens 3SF7844-8BB26-1SS1 is a Type 4 safety light curtain host receiver from the SIMATIC FS420I family, with 14 mm resolution and an 1800 mm protective height. The 14 mm detection capability means it catches fingers reaching into the hazard zone — finger-protection class per IEC 61496-1, suitable for hand-entry guarding around presses, assembly stations, and robotic cells. Blanking from 0 to 6 m allows the beam set to ignore fixed obstructions (e.g., a workpiece fixture) without disabling the entire curtain.
Integration and fieldbus
Communication is via Profisafe bus connection, which integrates directly into a SIMATIC FS420I safety controller over PROFINET with PROFIsafe profile. No separate safety relay needed for the bus interface — the host receiver reports status and diagnostics over the fieldbus, simplifying the safety CPU separation and reducing panel wiring.