IEC IEC61508-4 Edition2.02010-04 INTERNATIONAL STANDARD NORME INTERNATIONALE BASICSAFETYPUBLICATION PUBLICATIONFONDAMENTALEDESECURITE Functional safetyofelectrical/electronic/programmableelectronicsafety-related systems. Part4:Definitions and abbreviations Sécuritefonctionnelledessystemesélectriques/electroniques/electroniques programmablesrelatifsalasécurite Partie4:Definitionset abréviations INTERNATIONAL ELECTROTECHNICAL COMMISSION COMMISSION ELECTROTECHNIQUE INTERNATIONALE PRICECODE CODEPRIX ICS25.040.40;29.020 ISBN978-2-88910-527-4 - 2 - 61508-4 @ IEC:2010 CONTENTS FOREWORD INTRODUCTION Scope 2 Normative references 3 Definitions and abbreviations . 3.1 Safetyterms. 3.2 Equipment and devices 3.3 Systems - general aspects .15 3.4 Systems - safety-related aspects 3.5 Safety functions and safety integrity 19 3.6 Fault, failure and error (see Figure 4), 22 3.7 Lifecycle activities. 27 3.8 Confirmation of safety measures Bibliography ...32 Index 33 Figure 1 - Overall framework of the IEC 61508 series 8 Figure 2 - Programmable electronic system Figure 3-Electrical/electronic/programmable electronic system (E/E/PEsystem) structure and terminology. .16 Figure 4 - Failure model 23 Table 1 - Abbreviations used in this standard 61508-4 @ IEC:2010 INTERNATIONAL ELECTROTECHNICAL COMMISSION FUNCTIONAL SAFETYOFELECTRICAL/ELECTRONICI PROGRAMMABLE ELECTRONICSAFETY-RELATED SYSTEMS Part 4: Definitions and abbreviations FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees(IEC National Committees). international co-operation on all questions concerning standardization in the electrical and electronic fields.To this end and in addition to other activities, IEc publishes International Standards, Technical Specifications. Technical Reports, Publicly Available Specifications (PAS)and Guides (hereafter referred to as "TEC in the subject dealt with may participate in this preparatory work., International, governmental and non- governmental organizations liaising with the IEC also participate in this preparation. IEc collaborates closely agreementbetweenthetwoorganizations. interested IEC National Committees. 3)IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEc cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. between any IEc Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5)IEc itself does not provide any attestation of conformity. Independent certification bodies provide conformity assessment services and,in some areas,access to IEC marks of conformity.IEC is not responsible for any services carried out by independent certification bodies. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEc or its directors, employees, servants or agents including individual experts and members of its technical committees and IEcNational Committees for any personal injury,property damage or expenses arising out of the publication, use of, or reliance upon, this IEc Publication or any other IEC Publications. 8) Attention is drawn to the Normative references cited in this publication.Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEc Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International Standard IEC 61508-4 has been prepared by subcommittee 65A: System aspects, of IEc technical committee 65: Industrial-process measurement, control and automation. This second edition cancel