Customers who have Allen-Bradley 9000 series retro-reflective photo eyes should periodically clean and check the alignment to the reflector. Each eye provides visual feedback through status LEDs and a visible red beam which can be used to center the eye on the reflector.

The status LEDs show 

1. Input power (Yellow LED)
2. Output status (Green LED)
3. 2X output margin (Red LED)

Adjust the eye so all three LEDs are lit at the same time. When the eye is blocked (cannot see the reflector) only the yellow LED should be lit. Keeping the eye properly aligned and periodically cleaning the eye lens and reflector with a cotton cloth will help keep the eye functioning at its best.