Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
AI TechDocKnowledge

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.

By knowledge.aitechdoc.world · Published September 26, 2026 · Last reviewed

Source: IEC 60947-5-2, Low-voltage switchgear and controlgear — Part 5-2: Control circuit devices and switching elements — Proximity switches

Definitions follow the cited standards and specifications. Where a source is a copyrighted publication, such as an ISO, IEC or EN standard, the definition is a close paraphrase, not a verbatim quotation, so as not to infringe copyright. We recommend reading the original publication. The sections “How it applies” are editorial commentary by AI TechDoc Knowledge and are not part of any standard.

Seen a mistake? Send us a note!