Omron Retro-Reflective Photo Eye | E3K-R10K4-NR-1

The Omron E3K is a heavy-duty retro-reflective photo eye built specifically for door and gate control. One unit mounts on one side of the opening and bounces an infrared beam off a reflector on the opposite jamb, so wire only runs to one side. Break the beam and the relay drops out, stopping or reversing the door. A universal 24-240V AC/DC supply and a full DPDT relay are what let it drop straight into older contactor-driven commercial operators that were never designed around low-voltage two-wire sensors.

Will This Work On My Operator?

The E3K can be wired three different ways off the same terminal strip, which is why it fits both current and legacy control systems:

• Traditional non-monitored (dry contact): for older operators with a plain sensing-device input. Power to terminals 7 and 8, safety relay to terminals 4 (NC2) and 6 (C2).
• UL 325-2018 10K resistor method: power to terminals 7 and 8, safety relay to terminals 1 (C1) and 3 (NC1). The 10K resistor is built into this model — nothing to add.
• UL 325-2018 normally-closed method: power to terminal 7 (negative) and 8 (positive), safety relay to terminals 5 (NO2) and 6 (C2), with a jumper from terminal 6 to terminal 7.

Overhead Door Model SEL and SEL+: use the traditional non-monitored method. Overhead Door's external wiring diagram for these operators shows two-wire sensing devices landing across the C3 and SE terminals on the operator's control strip, and states that a sensing device should be installed if the door is to have momentary contact close. Without one, the operator has to be closed with constant pressure on the button. The SEL control circuit runs at 24 VAC off a 28 VAC 30VA transformer, well inside the E3K's supply range.

How to confirm before you buy: open the operator's electrical box and find the wiring diagram inside the cover. Look for terminals labelled SE, sensing edge, photocell, or reversing device. Note the control voltage while you're in there — anything from 24 to 240 V, AC or DC, works.

Specs:

Model: E3K-R10K4-NR-1
Sensing Method: Retro-reflective
Detecting Distance: 33 FT (10 m) with the included E39-R1 reflector; 40 FT (12 m) with a 3" diameter reflector
Minimum Detectable Object: 56 mm with E39-R1; 80 mm with a 3" reflector
Supply Voltage: 24 to 240 VAC ±10%, 50/60 Hz; 24 to 240 VDC ±10%
Power Consumption: 13.75 VA max; 3.75 W max (DC)
Control Output: DPDT relay, 10 A at 240 VAC / 10 A at 28 VDC
Operation Mode: Light-ON / Dark-ON, switch selectable
Response Time: 30 ms max
Light Source: 950 nm pulse-modulated infrared LED
Directional Angle: Sensor 0.5° to 3°; reflector 40° min
Indicators: Light Incident (red), Output Stability (green), Output Operation (yellow)
Connections: Screw terminal strip, 3/4-14 NPSM conduit hub
Enclosure: UL Type 1. Omron additionally rates the housing IEC 144 IP67 and NEMA 1, 4, 4X, 12 Indoor, 13 — see the note below
Operating Temp: -13°F to 131°F (-25°C to 55°C)
Operating Humidity: 45 to 85% RH
Housing: VALOX 553 PBT, PMMA lens, NBR seal, zinc-plated steel bracket
Dimensions: 7 5/16" H x 3 1/2" W x 2 1/2" D (4" deep with bracket)
Weight: 20.5 oz (580 g)
Approvals: UL Recognized, file E333436; UL 325-2018 and CSA-C22.2 No. 247-92 cRUus

Indoor or Outdoor?

We list this as an indoor sensor, and here's why. The only third-party enclosure listing on the E3K is UL Type 1, which is general purpose — no water protection. The IP67 and NEMA 4X figures come from Omron's own specification sheet, not from a UL enclosure listing, and Omron's instruction manual tells you plainly not to use the sensor in water, rain, or outdoors, and not to aim it into direct sunlight.

In practice these get installed on exterior openings all the time and many of them last for years. We're not going to promise that. If you're putting one outside, protect it: mount it under cover where you can, keep it out of direct spray and direct sun, and add a reflector hood. That's your call to make, not a rating we're claiming.

Kit Includes:

• (1) Omron E3K-R10K4-NR-1 retro-reflective photoelectric sensor
• (1) E39-R1 reflector
• (1) E39-L37 two-piece steel mounting bracket with hardware
• (1) LY2-DC12 plug-in relay output module, installed

Works With / Replaces:

• Direct replacement for an existing E3K-R10K4 or E3K-R10K4-NR installation.
• Also sold as the E3K-2018 through MMTC.
• Retrofit sensing device for older commercial operators with a two-wire sensing input, including the Overhead Door Model SEL and SEL+.
• Upgrade to a 3" diameter reflector to extend the range from 33 to 40 feet.
• Optional E39-T1, E39-T2 and E39-T3 timer modules add ON-delay, OFF-delay and one-shot timing.
• The LY2-DC12 relay module is plug-in replaceable — a failed output does not mean a failed sensor.

Installation Notes:

• Disconnect power to the operator before wiring.
• Mount the sensor and reflector at the same height on opposite sides of the opening, square to each other. The two-piece bracket gives a full 360° of horizontal rotation and tilts the sensor up to 45°; it secures with three 1/4-20 bolts at 120° spacing.
• Terminals accept up to 14 AWG solid. Tighten to 9.8 in-lb (1.1 N-m).
• Set the Light-ON / Dark-ON selector to Light ON for all three door and gate wiring methods.
• Turn the sensitivity potentiometer to maximum, then confirm the green stability LED stays lit across the full opening with the door moving.
• Do not run sensor wiring in the same conduit as line-voltage or motor leads. Use shielded cable if you have no choice.
• Do not power an AC-supplied sensor from a variable-frequency drive or other high-frequency source.
• The sensor needs 100 ms after power-up before it is live. If the sensor and the operator are on separate supplies, power the sensor first.

Warning: Impact damage can permanently compromise the housing seal. Mount it, don't drive it. Never use a constant-contact close to override a sensing device that isn't working, and test the reversal after installation and at every service call.