Through-beam slot sensor for part-present detection
The Omron EE-SX771 is a through-beam optical slot sensor with a 5 mm gap, designed for detecting the presence or absence of an object that interrupts the light beam. The NPN open-collector output is configured Dark-ON, meaning the output transistor turns on when the beam is blocked — the standard fail-safe wiring convention for this sensor class. It runs on a fixed 5 V supply and switches up to 35 mA, suitable for direct connection to a PLC input or logic gate. The chassis-mount package with M3 screw holes fits panel or machine-frame installations where a compact, fixed-gap sensor is needed for small-part detection, edge counting, or flag sensing in packaging, assembly, or light industrial automation.
5 mm gap and NPN Dark-ON output — fit and wiring
The 5 mm gap requires the vane to fit without rubbing. The NPN Dark-ON output pulls low when the beam is blocked.
Closest functional peer: EE-SPX305-W2A
The EE-SPX305-W2A shares the same 5 mm through-beam slot, NPN Dark-ON output, and 5 V supply, but uses a wire-lead connection instead of the EE-SX771's M3 screw terminals, and its temperature range is -10°C to 55°C versus -25°C to 55°C. If your panel wiring prefers a flying-lead pigtail and you can accept the narrower temperature floor, the EE-SPX305-W2A is a drop-in functional swap for the sensing job.