Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Protective devices and interlocks

Active opto-electronic protective device (AOPD)

Also known as: AOPD

In machine safety, an active opto-electronic protective device (AOPD) is an ESPE device that uses opto-electronic sensing to detect interruption of a protected field. Its own emitters and receivers create the field, as in safety light curtains and multi-beam light grids.

  • Machine safety
  • EU

In one sentence

An AOPD such as a safety light curtain senses a person by the interruption of its own light beams; it is ESPE covered by IEC 61496.

Example

A four-beam AOPD guards the access opening of a palletizing cell and stops the robot when a person walks through the beams.

How it applies

  • Machine safety: AOPDs are specified by type and detection capability (resolution). Finger, hand and body detection need different resolutions, and the resolution affects the minimum distance calculation.
  • Functional safety: The AOPD is only the sensing part of a safety function. The complete function, including logic and the stopping of the machine, must achieve the required Performance Level or SIL.
  • Design: An AOPD does not stop ejected parts and cannot prevent access by reaching over or around the field. Combine it with guards where needed.
  • Technical documentation: Record the device type, resolution, protective response time and mounting position. The instructions should cover the daily test with the test rod where the manufacturer requires one.

AOPD vs. laser scanner

An AOPD detects that its beams are interrupted. A safety laser scanner measures distance to reflecting objects and is covered by a different part of IEC 61496.

By knowledge.aitechdoc.world · Published September 25, 2026 · Last reviewed

Source: IEC 61496 series, Safety of machinery — Electro-sensitive protective equipment

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.

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