Safety light curtain for guarded zones
The Siemens 3SF7844-8TB06-1SS1 is a Type 4 safety light curtain host receiver from the SIMATIC FS420I family, with 14 mm resolution across a 450 mm protected height and a sensing range of 0 to 6 m. Type 4 per IEC 61496-1 means it delivers the highest level of fault tolerance and self-checking — suitable for guarding hazardous machinery where a failure could cause serious injury. The 14 mm resolution catches fingers reaching into the hazard zone (finger-protection class), which is the typical spec for press brakes, assembly stations, and robot cells.
PROFIsafe integration and bus connection
This host receiver communicates over PROFIsafe via the SIMATIC FS420I interface, so it folds directly into a Siemens safety CPU without a separate safety relay or gateway hack. The bus connection carries both the safety-related OSSD signals and diagnostic data on the same cable — no parallel wiring for the safety chain. Commissioning engineers will configure the safety parameters (range, blanking, restart interlock) through the FS420I parameter assignment tool, not through DIP switches on the unit.