Industrial Sensing Fundamentals – Light/Dark Operate

Written by: Andrew Bollinger

A key step in choosing an industrial sensor is to understand the operating mode of the sensor. With digital photoelectric sensors, the input and the output are characterized by one of two sensing terms: Light Operate or Dark Operate. Light Operate (LO) describes a condition in which a photoelectric sensor’s output energizes its load when the sensor “sees” a sufficient amount of light; in other words, no target is present or detected by the sensor. Dark Operate (DO), the complement of LO, is a condition in which the sensor output energizes its load when the target is present.

Click Here to view a chart for further clarification.

For additional details on choosing a sensor type refer to:
How do I choose the right sensor?
Industrial Sensing Fundamentals – Back to the Basics: NPN vs PNP

About Mark Sippel

Mark Sippel is the North American Product Marketing Manager for Object ID and Photoelectric sensors with Balluff NA.
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One Response to Industrial Sensing Fundamentals – Light/Dark Operate

  1. Hal says:

    Thanks, that explains it perfectly.

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