Simple and reliable gate entry!

No user controls and nothing to adjust.

Setup only requires mounting the one-piece RLK31 photoelectric sensor housing and then aligning to a reflector.

Entry into parking lots and parking garages

is often controlled by automated gate systems. The RLK31 reliably monitors the area below the gate and keeps it from accidently closing on vehicles or even people that might be in the way.
RLK31 photoelectric sensor

In automated gate systems,

the compact size and industry standard mounting of the RLK31 means it effortlessly integrates into the gate system housing. With no user controls and nothing to adjust, setup requires mounting and aligning the one-piece RLK31 housing to a reflector. Vehicles are detected, regardless of type or color.

The RLK31 photoelectric sensor for automated gate systems is simple to use and easy to setup.

    • Compact size
    • Easy integration into gate system housing
    • Long detection range - 9 m (30 ft)
    • Tamperproof housing - Nothing to adjust
    • Wide voltage range
    • Accepts both AC and DC voltages
    • Built-in relay - rated 3A, SPDT

RLK31 photoelectric sensor


Polarized Retroreflective Sensors

RLK31 Sensing Modes


Polarized retroreflective mode sensors have both the transmitter and receiver in the same housing and use a corner-cube reflector to establish a light path. The target is detected when it blocks the beam from the sensor to the reflector.

A polarized filter in the lens of the sensor allows only light at a certain phase angle into the receiver. This enables the sensor to see a shiny object as a target and not incorrectly as a reflector. A corner-cube reflector causes a phase shift in the light waves that would not occur from light reflected from a shiny, reflective target. A polarized retro-reflective sensor must be used with a corner-cube reflector. These reflectors have the ability to accurately return the light energy, on a parallel axis, back to the sensor.

Technology Guide
Sensors for the Protection and Movement of People and Vehicles

Invisible Protection

Pepperl+Fuchs offers a wide range of sensors that are tailored to the gate, door and elevator industry. This includes sensors that can detect direction and differentiate between people and vehicles, sensors that monitor elevator doors and sliding or swinging doors, and sensors that provide absolute position and protection against pinch points and collisions. No matter the application, Pepperl+Fuchs has a sensor to suit your needs.

Download your copy of   Invisible Protection - Sensors for the Protection and Movement of People and Vehicles.

RLK31 Retroreflective Sensors

RLK31 Sensors
The RLK31 retro-reflective sensor features a universal AC/DC power supply that works on voltages from 12-240V DC and 24-240V AC. The built-in 3A SPDT relay is powerful enough to control the gate motor. While the waterproof (IP67) construction means it´s perfect for indoor or outdoor use.
RLK31 Retroreflective Sensors Accessories
RLK31 Accessories
Along with standard, right angle mounting brackets, a rugged shroud bracket is available for RLK31. The shroud bracket is perfect for installations when the RLK31 is unable to mount in the gate system housing or requires a free-standing mounting.

Made of zinc-plated steel, the shroud bracket protects the sensor on the top and two sides from accidental contact which can occur and damage the sensor. The shroud bracket features a variety of slotted mounting holes which allow multiple mounting options. And with a variety of slotted holes, the RLK31 mounts and can be angled which helps align the sensor to the reflector.

Gate Sensors

Model NumberFeatures
RLK31-54/25/31/115Sensor with 9m range, 2m cabled, AC/DC supply, SPDT relay
RLK31-54/25/31/115 SETSensor, OMH-RL31-01 bracket, and REF-C110-2 reflector

Gate Sensor Accessories

Model NumberFeatures
OMH-RL31-01Wide mounting bracket for all RLK31 sensors
OMH-RL31-02Narrow mounting bracket for all RLK31 sensors
OMH-RL31-03Shroud bracket for all RLK31 sensors; extra protection by enclosing sensor on three sides
REF-C110-23 inch round reflector with center mounting hole
Reflector Weather CapReflector weather cap/hood for REF-C110-2 reflector

Simplified Installation

Simplified InstallationLarge, industrial garage doors utilize a retroreflective photoelectric sensor to reliably detect when vehicles are in the gate path. The RLK31 is used because its one-piece design consists of an emitter and a receiver in the same housing. This one-piece design simplifies installation because a power source is required only on one side of the garage door. Since a reflector is mounted on the other side, a separate power source is not required.

External Mounting

External MountingThe RLK31 has a waterproof IP67 rating, perfect for installations that require it to be externally mounted. Gate housings often have built-in shrouds specifically for an external mounted sensor. A variety of mounting accessories are also available, including a shroud bracket which protects the RLK31 on three sides from accidental damage.

Multi-System Use

Multi-System UseA parking garage using a roll up gate system, rather than an actual gate arm. The application is still the same, requiring a photoelectric sensor to safely detect vehicles and people in the path before lowering the gate. The RLK31 is discretely tucked away behind the gate and creates an invisible path across the door opening to the reflector on the other side.

Easy Integration

Easy IntegrationBecause of its small size, the RLK31 easily integrates into the automated gate system housing. Since there is nothing to adjust, installation only requires aligning the RLK31 to the reflector. The wide voltage range is compatible with a variety of gate systems and the built-in 3A relay can also control the gate motor.

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