Photo Eyes and Edge Sensors: What They Do and Why

Safety equipment on an automated gate is not an upsell and it is not optional. Here is what each part does and how to tell it still works.

Photo eyes

An infrared beam across the opening. Break it and the gate stops or reverses. They cover the gap, which is where a car or a person usually is.

They need line of sight to each other and they collect dirt, which is why they are the commonest cause of a gate that will not close.

Edge sensors

A pressure-sensitive strip along the closing edge of the gate that reacts to contact. Photo eyes cover the gap; edges cover the gate itself.

On a large or fast gate, having both is the difference between a safe installation and one that relies on a single point of failure.

Force settings

Every operator has an adjustable force limit. Set correctly, the gate stops when it meets resistance rather than pushing through it.

The dangerous shortcut is turning force up so a gate pushes past a mechanical fault. If a gate needs more force than it used to, something is wrong with the gate.

Testing yours

Wave something through the beam while the gate closes and confirm it stops or reverses. Offer light resistance to the closing edge and confirm the same.

Fifteen minutes once a year. If either test fails, treat it as urgent rather than an inconvenience.

If a previous installer bypassed something

It happens, usually to make an intermittent fault go away. A gate with a sensor disconnected is heavy machinery with nothing to tell it something is in the way.

We will tell you if we find it, and we will not put a system back into service that way.