What it is and where it fits
The Omron F3SG-4RR1920-14 is a light curtain sensor — a safety-rated optoelectronic device that creates an invisible detection zone across a guarded opening. It is designed to stop hazardous machine motion when an object (typically a hand or body part) breaks the beam array, meeting the requirements of IEC 61496 for electro-sensitive protective equipment (ESPE).