IEC 62551-2012 PDF

Full title and description

Analysis techniques for dependability — Petri net techniques (IEC 62551:2012). This international standard specifies a Petri‑net based methodology to model systems for dependability purposes, to analyse those models and to present analysis results focused on reliability, availability, production availability, maintainability and certain safety‑related measures (for example SIL‑related metrics).

Abstract

IEC 62551:2012 provides structured guidance for building Petri‑net models (untimed, timed and high‑level nets, including common extensions and hierarchical constructs), for applying a six‑step dependability modelling and analysis process, and for reporting results so they can be used in dependability and safety assessments. The standard is intended to support consistent modelling practice and to improve repeatability and traceability of dependability analyses.

General information

• Status: Published / current international standard (stable publication with national adoptions reported).
• Publication date: 2 October 2012 (Edition 1.0).
• Publisher: International Electrotechnical Commission (IEC), TC 56 Dependability.
• ICS / categories: 21.020 (Dependability; reliability, availability, maintainability and safety).
• Edition / version: Edition 1.0 (2012).
• Number of pages: 136 pages (official IEC publication page count).

Scope

The standard defines a Petri‑net based methodology for dependability analysis covering modelling constructs (including weighted/inhibitor arcs, timed transitions, high‑level tokens and hierarchical constructs), guidance on model structuring and refinement, recommended analysis approaches (stochastic and deterministic timing, reachability and reward‑based measures), and conventions for presenting and documenting dependability results so they can inform reliability, availability, maintainability and safety assessments. It explicitly addresses how Petri nets can be used to represent system behaviour and maintenance/operational actions relevant to dependability.

Key topics and requirements

• Petri net fundamentals: untimed low‑level nets, timed nets, and high‑level Petri nets; symbols and notation for dependability modelling.
• Modelling constructs and extensions: weighted arcs, inhibitor/test arcs, multiple/fused places, superplaces/supertransitions and global variables for compact, modular models.
• Six‑step dependability modelling and analysis process: system description, submodel structure, model refinement, analysis, result representation and documentation.
• Support for timed and stochastic behaviours, deterministic transitions, reward structures and metrics for reliability, availability, production availability and maintainability.
• Guidance on hierarchical modelling and use of high‑level nets to manage complexity and improve readability for industrial‑scale systems.

Typical use and users

Engineers and analysts performing dependability, reliability and safety assessments; safety and functional‑safety practitioners (for SIL justification and safety cases); system architects modelling operational and maintenance activities; academic researchers working on stochastic models and Petri nets; and tool vendors implementing Petri‑net modelling and analysis features for dependability applications. The standard is used where a formal graphical model of behaviour and maintenance/recovery logic is required to compute or demonstrate dependability measures.

Related standards

IEC 62551 is related to other dependability and modelling standards, notably the IEC 61508 series for functional safety (cross‑referenced for SIL‑related measures) and ISO/IEC documents on high‑level Petri nets (for formal net definitions and syntax). It has also been adopted/endorsed as a European standard (EN 62551) without modification.

Keywords

Petri net, dependability, reliability, availability, production availability, maintainability, safety, SIL, stochastic modelling, timed Petri nets, high‑level Petri nets, hierarchical modelling.

FAQ

Q: What is this standard?

A: IEC 62551:2012 is an international standard that specifies a Petri‑net based methodology for dependability analysis of systems, giving modelling conventions, analysis guidance and reporting practices for dependability measures.

Q: What does it cover?

A: It covers Petri‑net fundamentals and extensions relevant to dependability (untimed, timed and high‑level nets), recommended modelling constructs, a six‑step modelling and analysis process, treatment of timing and stochastic behaviour, and guidance on presenting analysis results for reliability, availability, maintainability and certain safety measures.

Q: Who typically uses it?

A: Reliability and safety engineers, dependability analysts, system architects, researchers in formal modelling and tool vendors building Petri‑net analysis capabilities—essentially anyone needing a traceable Petri‑net approach to quantify or demonstrate dependability.

Q: Is it current or superseded?

A: IEC 62551 was published in 2012 (Edition 1.0). According to IEC publication metadata it is a stable international standard (publication date 2 October 2012) and national adoptions exist; users should check their national standards body for adoption/supersession status and for any corrigenda or amendments.

Q: Is it part of a series?

A: IEC 62551 stands as a standalone international standard for Petri‑net techniques in dependability analysis but is conceptually linked to other dependability and modelling standards (for example the IEC 61508 family for functional safety and ISO/IEC documents on Petri nets/high‑level nets). National and regional adoptions (EN 62551) exist.

Q: What are the key keywords?

A: Petri net; dependability; reliability; availability; maintainability; safety; timed/stochastic modelling; hierarchical Petri nets; SIL.