Glossary · Sensors and measurement
Diffuse-reflective photoelectric sensor
Also known as: Diffuse sensor, Proximity photoelectric sensor
German: Lichttaster
In industrial automation, a diffuse-reflective photoelectric sensor is a photoelectric sensor with emitter and receiver in one housing that detects an object when light reflected by the object itself reaches the receiver. No separate reflector or receiver is needed.
- Sensors
- Standards
In one sentence
A diffuse-reflective photoelectric sensor detects objects by the light they reflect back into the sensor, without a reflector or separate receiver.
Example
A diffuse-reflective photoelectric sensor with background suppression detects cartons on a conveyor and ignores the machine frame behind them.
How it applies
- Engineering: The detection range depends on the color, surface and size of the object. Variants with background suppression evaluate the distance and are less sensitive to object color and bright backgrounds.
- Commissioning: Teach or adjust the sensor with the real objects and background. Shiny or dark objects are the usual edge cases.
- Safety: A standard diffuse-reflective sensor is not a protective device. Detecting persons for safeguarding requires devices designed and rated for that purpose, such as those covered by IEC 61496.
- Documentation: Describe the sensor's function and adjustment in the operating manual, and state clearly where a sensor only serves process detection and must not be relied on for protection.
Diffuse-reflective sensor vs. through-beam sensor
A diffuse-reflective sensor needs only one device but has a shorter range and depends on the object's surface. A Through-beam photoelectric sensor uses separate emitter and receiver, has a longer range and detects the object by interrupting the beam.