Glossary Updates12 new terms added to the glossaries · October 2, 2026, 22:44 CEST
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Glossary · Automation software engineering and architecture

Time-triggered execution

Also known as: Time-triggered architecture, Cyclic execution

German: Zeitgesteuerte Ausführung

In real-time systems, time-triggered execution is an execution model in which tasks or communications are started at predefined points in time from a global schedule, rather than in response to events.

  • Software engineering

In one sentence

Time-triggered execution starts tasks or communications at predefined times from a schedule rather than in response to events.

Example

The PLC reads inputs, executes the program and writes outputs every 4 ms, regardless of whether any input has changed.

How it applies

  • Engineering: Time-triggered systems are predictable and easy to analyze, because load does not depend on events. Cyclic PLC tasks and time-scheduled fieldbuses are classic examples.
  • Design: Events are detected only at the next cycle, which sets a maximum reaction delay of about one period plus processing. Very short events can be missed unless latched.
  • Documentation: Technical data should state cycle times and resulting reaction times. Users need to know that signals shorter than a cycle may not be detected without special inputs.

Time-triggered vs. event-triggered execution

Time-triggered execution runs on a schedule; Event-triggered execution runs when something happens. Event triggering reacts faster and uses fewer resources when idle but is harder to analyze under bursts.

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

Source: AI TechDoc Knowledge editorial definition, based on real-time systems practice (Kopetz)

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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