Genuine LiftMaster LMRRUL — the monitored retro-reflective photo eye LiftMaster ships with its UL 325 gate operators and specifies for every additional entrapment zone. One powered sensor and one passive reflector give a beam of up to 50 ft, so only one side of the gate needs wiring. It has a built-in heater, a steel sensor hood, NEMA 4X housings and an alignment LED that tells you when the beam is optimal instead of merely made. The operator supervises it every cycle, which is what "monitored" means and what the 2016 and 2018 revisions of UL 325 require.
LMRRUL, LMRRU or LMTBUL? LMRRU is the earlier number for this eye; order LMRRUL where a manual calls for LMRRU. The LMTBUL is the through-beam version: emitter and receiver on opposite sides, 90 ft range, for wide lanes and long approaches. For the gate edge itself use a monitored resistive edge or the LMWEKITU wireless edge kit — a photo eye covers the space in front of the gate, not the pinch point on it.
Specifications
| Part number | LMRRUL (earlier number LMRRU) |
|---|---|
| Type | Monitored retro-reflective photoelectric sensor with reflector |
| Range | Up to 50 ft |
| Sensor supply | 6.8 VDC, 20 mA, from the operator's monitored eye terminals |
| Heater | Built in: 10–40 VDC or 8–28 VAC, 2 W (170 mA at 12 V, 85 mA at 24 V) |
| Rating | NEMA 4X sensor and reflector; meets UL 325 |
| Alignment | LED — solid blue optimal, blinking blue near, solid red misaligned or blocked |
| In the box | Sensor with steel hood and bracket, reflector with polyethylene hood and bracket, wire cover, 10 ft cable, mounting screws and lock nuts |
| Fits | LiftMaster gate operators with monitored entrapment inputs (list below) |
| Condition | Genuine LiftMaster, new |
Operators it fits
| Operator | Note |
|---|---|
| CSL24UL, CSW24UL | Commercial 24VDC — one LMRRUL / LMRRU ships in the box |
| INSL24UL, IHSL24UL | Industrial 24VDC — one ships in the box |
| HDSL24UL, HDSW24UL | Heavy-duty 24VDC |
| LA400UL, LA412UL, LA500UL | Swing arms — listed in the LA400 / LA412 / LA500 UL addendum |
| RSL12UL, RSW12UL | Residential 12VDC |
| SL3000UL, CSW200UL | Commercial AC |
| SL585UL, SL595UL | Industrial AC — see SL585 / SL595 parts |
| Maxum JDC / RJDC / JHDC / TDC | Industrial DC door operators — see Maxum accessories |
Where it goes
Across the path of the gate on the side that has no edge: for a slide gate, across the opening in front of the leading edge and, on the trailing side, between the gate and whatever it closes toward; for a swing gate, across the arc on the road side. Mount the sensor and reflector at the same height, aim the sensor until the LED goes solid blue, then torque the bracket and fit the set screw. The 10 ft cable goes to the operator's monitored eye input — check the manual for which terminals are open and which close.
Is the eye actually the problem?
A photo eye is blamed for most "gate will not close" calls, and most of the time it is doing its job. Work down this list first:
| Symptom | Check first |
|---|---|
| Gate opens but will not close, no error | The photo eye first: LED red means blocked or misaligned. Clean the reflector, re-aim, check for a spider web or a bumper in the beam. |
| Closes only while the button is held | A monitored device is missing or faulted. The operator falls back to constant-pressure close until it sees the eye. |
| Eye LED dead | The eye terminals on the board, the cable and the wire cover where it enters the housing. The sensor draws power from the operator; a dead LED is almost always the cable. |
| Works in the day, fails at night or in fog | Alignment is marginal. Solid blue is optimal; blinking blue will drop out in rain. Re-aim. |
| Reverses on cold mornings | Check the heater supply terminals are wired; the heater keeps the lens clear of condensation. |
Common questions
Monitored or non-monitored — what is the difference?
A monitored eye is tested by the operator on every cycle; if it fails the test the gate will not close automatically. Operators built to UL 325-2016 and later require monitored devices and will not accept an unmonitored eye on the monitored input.
Does it work on other makes of operator?
It is designed for LiftMaster's monitored inputs. Some other operators with a compatible pulsed input accept it, but we cannot guarantee that and LiftMaster does not list it.
One eye or two?
One per entrapment zone. A slide gate normally needs an eye across the opening and a second across the trailing space; a swing gate needs one on each side of the leaf that has no edge.
What about the reflector in direct sun?
Fit the supplied hoods and, where the sun is low across the lane, put the sensor on the sunny side looking away from it.
Related
LMTBUL through-beam photo eye · LMWEKITU wireless edge kit · S505AL monitored edge · all safety devices and loop detectors · LiftMaster slide gate operators · LiftMaster swing gate operators
Not sure whether your operator takes a monitored eye, or how many zones need one? Send the operator model and a photo of the gate to parts@gatehousesupplies.com or call 866-965-5599. We would rather confirm it than have you order twice.
