15 m through-beam — where the range matters
The E3RBTP21OMI is a through-beam photoelectric sensor from Omron's E3RB series, built for applications that need a clean break across a gap up to 15 m. That range puts it squarely in conveyor divert gates, long-travel crane end-of-travel, or pallet presence at the far end of a stretch — places a retroreflective or diffuse sensor would drift on target reflectance or background colour. The emitter and receiver are separate housings, so alignment is fixed at install but the detection is absolute — no false triggers from a dusty reflector or a shiny product passing through the beam.
IP67/IP69K — washdown-ready, not just splash-proof
Rated IP67 and IP69K, the sensor body and optics survive high-pressure hot-water washdown cycles typical in food-and-beverage or pharmaceutical lines. The M12 connector's O-ring is the wet-end seal — torque it to the mating cordset per the manufacturer's spec or the IP69K rating drops to IP67 on that face. Temperature range -25 °C to 55 °C covers most indoor process environments but not freezer tunnels; a cold-storage line would need a sensor rated below -25 °C.
PNP output, 100 mA, 500 µs — what the PLC sees
PNP sourcing output at 100 mA max — direct-connected to a standard 24 VDC PLC input module without a pull-up resistor or interposing relay for most loads. The 500 µs response time is fast enough for counting parts on a 2 m/s conveyor (the beam break is ~7.5 ms at that speed), but too slow for high-speed ejection at 10+ m/s where a sub-100 µs sensor would be needed. Light-ON / Dark-ON selectable via a switch on the housing — one sensor covers both presence and absence detection without rewiring or adding a NOT in the PLC logic.
M12 4-pin connector — panel fit and swap
Terminated with an M12 4-pin male connector. The pinout matches the industry-standard photoelectric sensor wiring (pin 1 = brown/B+, pin 2 = white/not used or output, pin 3 = blue/B-, pin 4 = black/output). That means it drops into a panel wired for an older E3S-C or E3JK sensor with the same M12 cordset — no re-pulling cables or changing the connector block. Length is 61 mm, so it fits the same mounting bracket footprint as the E3S-C series (57 mm body length) — the extra 4 mm is in the connector boss, not the mounting hole spacing.