Through-beam slot sensor with PNP dark-ON output
The Omron EE-SX771P is a through-beam photoelectric sensor with a 5 mm slot width, designed for part-present detection in assembly and packaging machinery. Its PNP open-collector output switches dark-ON — the transistor turns on when the beam is interrupted, which is the standard logic for detecting an object in the gap. The 5 V supply rail ties it to legacy PLC input banks or regulated 5 V supplies common in small automation panels.
5 V rail and switching current
The sensor operates on a fixed 5 V supply — no wide-range regulator inside, so the board or cabinet supply must hold 5 V ± tolerance. The switching current is rated at 30 mA, which drives a standard PLC digital input or a small relay directly. If your input card expects NPN sinking, this PNP sourcing output requires a pull-down resistor or a different sensor — the EE-SPX305-W2A is the NPN dark-ON sibling.
Mounting and temperature limits
Chassis mount with M3 screws — no DIN-rail clip, so plan for a drilled bracket or panel. The operating range of -25°C to 55°C covers indoor factory floor ambient but not freezing storage or hot cabinet interiors above 55°C. For colder environments, the EE-SPX305-W2A and EE-SPX613 have a -10°C low end, which is a tighter cold limit.
The EE-SX771P is listed as Active — no end-of-life or last-time-buy notice. For dual-sourcing resilience, the EE-SPX305-W2A is a functional alternative with the same 5 mm slot and 5 V supply but NPN output — verify polarity compatibility before substituting.