Photoelectric Sensors, Selection Guidelines

Selecting Photoelectrics

Now that you have an understanding of some basic terminologies associated with photoelectric sensing, it's time to move on and select a sensor. The first thing you have to decide, when selecting a photo eye, is what sensing mode to use. There are four.

Sensing Modes

Dark operate means that you'll get an output when the sensor cannot detect its own light. This is usually true of opposed mode photo eyes. In normal condition, the emitter directs light straight across to the receiver lens. When a target comes along and blocks the effective beam, the receiver can no longer detect light. It's "dark", and you get an output.