prEN IEC 61508-4:2025
(Main)Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 4: Definitions and abbreviations
Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 4: Definitions and abbreviations
Funktionale Sicherheit sicherheitsbezogener elektrischer/elektronischer/programmierbarer elektronischer Systeme - Teil 4: Begriffe und Abkürzungen
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques programmables relatifs à la sécurité - Partie 4: Définitions et abréviations
Funkcijska varnost električnih/elektronskih/elektronsko programirljivih varnostnih sistemov - 4. del: Definicije in kratice
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Standards Content (Sample)
SLOVENSKI STANDARD
01-april-2025
Funkcijska varnost električnih/elektronskih/elektronsko programirljivih varnostnih
sistemov - 4. del: Definicije in kratice
Functional safety of electrical/electronic/programmable electronic safety-related systems
- Part 4: Definitions and abbreviations
Funktionale Sicherheit sicherheitsbezogener
elektrischer/elektronischer/programmierbarer elektronischer Systeme - Teil 4: Begriffe
und Abkürzungen
Sécurité fonctionnelle des systèmes électriques/électroniques/électroniques
programmables relatifs à la sécurité - Partie 4: Définitions et abréviations
Ta slovenski standard je istoveten z: prEN IEC 61508-4:2025
ICS:
01.040.25 Izdelavna tehnika (Slovarji) Manufacturing engineering
(Vocabularies)
25.040.40 Merjenje in krmiljenje Industrial process
industrijskih postopkov measurement and control
35.240.50 Uporabniške rešitve IT v IT applications in industry
industriji
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
65A/1166/CDV
COMMITTEE DRAFT FOR VOTE (CDV)
PROJECT NUMBER:
IEC 61508-4 ED3
DATE OF CIRCULATION: CLOSING DATE FOR VOTING:
2025-02-14 2025-05-09
SUPERSEDES DOCUMENTS:
65A/1059A/CD, 65A/1078A/CC
IEC SC 65A : SYSTEM ASPECTS
SECRETARIAT: SECRETARY:
United Kingdom Ms Stephanie Lavy
OF INTEREST TO THE FOLLOWING COMMITTEES: HORIZONTAL FUNCTION(S):
TC 8,TC 9,TC 22,TC 31,TC 44,TC 45,TC 56,TC 61,TC
62,TC 65,SC 65B,SC 65C,SC 65E,TC 66,TC 72, TC
77,TC 80,TC 108,SyC AAL,SyC SM,SC 41
ASPECTS CONCERNED:
Safety
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TITLE:
Functional safety of electrical/electronic/programmable electronic safety-related systems - Part
4: Definitions and abbreviations
PROPOSED STABILITY DATE: 2028
NOTE FROM TC/SC OFFICERS:
electronic file, to make a copy and to print out the content for the sole purpose of preparing National Committee positions.
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IEC CDV 61508-4 ED3 © IEC 2025 2 65A/1166/CDV
1 CONTENTS
2 FOREWORD . 4
3 INTRODUCTION . 6
4 1 Scope . 8
5 2 Normative references . 10
6 3 Definitions and abbreviations . 10
7 3.1 Safety terms . 11
8 3.1.15 human factors , ergonomics usability and interaction
9 between persons and products, devices, services, systems and
10 environments, both real and virtual . 13
11 3.1.16 human error discrepancy between the human action
12 taken or omitted, and the intended or required . 13
13 3.2 Equipment and devices . 13
14 3.2.17 direct verification verification of a software tool’s
15 output that does not depend upon any other software tool . 15
16 3.2.18 indirect verification verification of a software
17 tool’s output that depends upon one or more other software tool(s) or
18 verification of software tool’s output after integration with one or more
19 elements of the system. . 15
20 3.2.19 software lifecycle data all data produced during the software lifecycle . 15
21 3.3 Systems – general aspects . 16
22 3.4 Systems – safety-related aspects . 17
23 3.5 Safety functions and safety integrity. 19
24 3.5.16 low demand mode . 22
25 3.5.17 high demand mode . 22
26 3.5.18 continuous demand mode . 22
27 3.6 Fault, failure and error (see Figure 6). 22
28 3.7 Lifecycle activities . 29
29 3.7.6 Formal methods . 29
30 3.8 Confirmation of safety measures . 30
31 3.9 Selection of techniques and measures . 33
32 4 Figures and illustrations for definitions and abbreviations . 34
33 4.1 General . 34
34 4.2 Programmable electronic system . 34
35 4.3 E/E/PE system . 35
36 4.4 E/E/PE safety-related system . 35
37 NOTE Subsystem A is a multi-channel subsystem and subsystems B & C are single
38 channel subsystems. . 36
39 4.5 E/E/PE safety-related system . 36
40 4.6 Overall safety function . 37
41 Index . 40
43 Figure 1 – Overall framework of the IEC 61508 series . 9
44 Figure 2 – Programmable electronic system. 34
45 Figure 3 – Electrical/electronic/programmable electronic system (E/E/PE system) –
46 structure and terminology . 35
47 Figure 4 – Physical diagram of the key concepts of E/E/PE safety-related system,
48 subsystem (see 3.4.4) and element (see 3.4.5) . 35
IEC CDV 61508-4 ED3 © IEC 2025 3 65A/1166/CDV
Figure 5 – Failure model . 36
51 Table 1 – Abbreviations used in this standard . 10
IEC CDV 61508-4 ED3 © IEC 2025 4 65A/1166/CDV
54 INTERNATIONAL ELECTROTECHNICAL COMMISSION
55 ____________
57 FUNCTIONAL SAFETY OF ELECTRICAL/ELECTRONIC/
58 PROGRAMMABLE ELECTRONIC SAFETY-RELATED SYSTEMS –
60 Part 4: Definitions and abbreviations
62 FOREWORD
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91 8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
92 indispensable for the correct application of this publication.
93 9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
94 patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
95 respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
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97 the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
98 shall not be held responsible for identifying any or all such patent rights.
99 IEC 61508-4 has been prepared by subcommittee 65A: System aspects, of IEC technical
100 committee 65: Industrial-process measurement, control and automation.
101 This third edition cancels and replaces the second edition published in 2010. This edition
102 constitutes a technical revision.
103 This edition has been subject to a thorough review and incorporates many comments received
104 at the various revision stages.
105 This edition includes the following significant technical changes with respect to the previous
106 edition (the following list does refer to this document; other parts do mention specific further
107 details):
IEC CDV 61508-4 ED3 © IEC 2025 5 65A/1166/CDV
a) Document was upgraded to the 2024 version of the ISO/IEC Directives; this does
109 introduce a significant number of editorial changes, clause renumbering,rewording of the
110 information provided in Notes and editing of definitions (e.g. figures and illustratons are
111 moved to clause 4 and referenced by relevant defintions);
112 b) Set of defintions introduced to cover aspects of:
113 i) software off-line support tools;
114 ii) software technology classes (‘artificial Intelligence’)
115 iii) diagnostic functions;
116 iv) levels of independence;
117 v) selection of techniques and methods (shortcuts in tables)
118 c) Various clarifications in defintions and minor editorial errors have been corrected; the
119 normative references and the bibliography has been updated.
120 It has the status of a basic safety publication according to IEC Guide 104.
121 The text of this document is based on the following documents:
Draft Report on voting
65A/XX/FDIS 65
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