SIST EN IEC 61800-5-3:2024

SLOVENSKI STANDARD
01-april-2024
Električni pogonski sistemi z nastavljivo hitrostjo - 5-3. del: Varnostne zahteve -
Funkcionalne, električne in okoljske zahteve za kodirnike (IEC 61800-5-3:2021)
Adjustable speed electrical power drive systems - Part 5-3: Safety requirements -
Functional, electrical and environmental requirements for encoders (IEC 61800-5-
3:2021)
Elektrische Leistungsantriebssysteme mit einstellbarer Drehzahl - Teil 5-3:
Anforderungen an die Sicherheit von Encodern (Gebern) - Funktional, elektrisch und
umwelttechnisch (IEC 61800-5-3:2021)
Entraînements électriques de puissance à vitesse variable - Partie 5-3: Exigences de
sécurité - Exigences fonctionnelle, électrique et environnementale pour codeurs (IEC
61800-5-3:2021)
Ta slovenski standard je istoveten z: EN IEC 61800-5-3:2023
ICS:
29.200 Usmerniki. Pretvorniki. Rectifiers. Convertors.
Stabilizirano električno Stabilized power supply
napajanje
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61800-5-3

NORME EUROPÉENNE
EUROPÄISCHE NORM October 2023
ICS 29.200; 29.130.99; 13.110
English Version
Adjustable speed electrical power drive systems - Part 5-3:
Safety requirements - Functional, electrical and environmental
requirements for encoders
(IEC 61800-5-3:2021)
Entraînements électriques de puissance à vitesse variable - Elektrische Leistungsantriebssysteme mit einstellbarer
Partie 5-3: Exigences de sécurité - Exigences fonctionnelle, Drehzahl - Teil 5-3: Anforderungen an die Sicherheit von
électrique et environnementale pour codeurs Encodern (Gebern) - Funktional, elektrisch und
(IEC 61800-5-3:2021) umwelttechnisch
(IEC 61800-5-3:2021)
This European Standard was approved by CENELEC on 2021-03-30. CENELEC members are bound to comply with the CEN/CENELEC
Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC
Management Centre or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61800-5-3:2023 E

European foreword
The text of document 22G/431/FDIS, future edition 1 of IEC 61800-5-3, prepared by SC 22G
"Adjustable speed electric power drive systems (PDS)" of IEC/TC 22 "Power electronic systems and
equipment" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2024-04-20
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-10-20
document have to be withdrawn
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61800-5-3:2021 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
ISO 12100:2010 NOTE Approved as EN ISO 12100:2010 (not modified)
IEC 61508 (series) NOTE Approved as EN 61508 (series)
IEC 61511 (series) NOTE Approved as EN 61511 (series)
IEC 61513 NOTE Approved as EN 61513
IEC 62061 NOTE Approved as EN IEC 62061
IEC 61709:2017 NOTE Approved as EN 61709:2017 (not modified)
IEC 61508-4:2010 NOTE Approved as EN 61508-4:2010 (not modified)
IEC 61508-6:2010 NOTE Approved as EN 61508-6:2010 (not modified)
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Publication Year Title EN/HD Year
IEC 60068-2-1 - Environmental testing - Part 2-1: Tests - Test EN 60068-2-1 -
A: Cold
IEC 60068-2-47 - Environmental testing - Part 2-47: Test - EN 60068-2-47 -
Mounting of specimens for vibration, impact
and similar dynamic tests
IEC 60335-1 - Household and similar electrical appliances - - -
Safety - Part 1: General requirements
IEC 60947-5-2 2019 Low-voltage switchgear and controlgear - Part EN IEC 60947-5-2 2020
5-2: Control circuit devices and switching
elements - Proximity switches
- - + A11 2022
IEC 61000-6-7 2014 Electromagnetic compatibility (EMC) - Part 6-7: EN 61000-6-7 2015
Generic standards - Immunity requirements for
equipment intended to perform functions in a
safety-related system (functional safety) in
industrial locations
IEC 61508-2 2010 Functional safety of EN 61508-2 2010
electrical/electronic/programmable electronic
safety-related systems - Part 2: Requirements
for electrical/electronic/programmable
electronic safety-related systems (see
http://www.iec.ch/functionalsafety Functional
Safety and IEC 61508)
IEC 61800-1 1997 Adjustable speed electrical power drive EN 61800-1 1998
systems - Part 1: General requirments - Rating
specifications for low voltage adjustables
speed d.c. power drive systems
IEC 61800-5-1 2007 Adjustable speed electrical power drive EN 61800-5-1 2007
systems - Part 5-1: Safety requirements -
Electrical, thermal and energy
+ A1 2016 + A1 2017
- - + A11 2021
Publication Year Title EN/HD Year
IEC 61800-5-2 2016 Adjustable speed electrical power drive EN 61800-5-2 2017
systems - Part 5-2: Safety requirements -
Functional
IEC 62368-1 2018 Audio/video, information and communication EN IEC 62368-1 2020
technology equipment - Part 1: Safety
requirements
ISO 13849-1 2015 Safety of machinery - Safety-related parts of - -
control systems - Part 1: General principles for
design
ISO 13849-2 2012 Safety of machinery - Safety-related parts of EN ISO 13849-2 2012
control systems - Part 2: Validation

IEC 61800-5-3 ®
Edition 1.0 2021-02
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Adjustable speed electrical power drive systems –

Part 5-3: Safety requirements – Functional, electrical and environmental

requirements for encoders
Entraînements électriques de puissance à vitesse variable –

Partie 5-3: Exigences de sécurité – Exigences fonctionnelle, électrique et

environnementale pour codeurs
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 13.110; 29.130.99; 29.200 ISBN 978-2-8322-9400-0

– 2 – IEC 61800-5-3:2021 © IEC 2021
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 10
2 Normative references . 11
3 Terms and definitions . 12
4 Safety sub-functions . 20
4.1 General . 20
4.2 Safe incremental position (SIP) . 20
4.3 Safe absolute position (SAP) . 20
4.4 Safe speed value (SSV) . 20
4.5 Safe acceleration value (SAV) . 20
4.6 Safety sub-functions for evaluation and signalling . 21
5 Management of functional safety . 21
6 Requirements for design and development . 21
6.1 General requirements . 21
6.2 Design standards . 25
6.3 Fault detection . 25
6.4 Design requirements for specific types of Encoder(SR) . 26
6.4.1 Design requirements for Encoder(SR) with sine and cosine output
signals . 26
6.4.2 Design requirements for Encoder(SR) with incremental and absolute
output signals . 27
6.4.3 Design requirements for Encoder(SR) with square wave signal interface . 28
6.4.4 Design requirements for Resolver . 28
6.5 Design requirements regarding mechanics . 29
6.5.1 General . 29
6.5.2 Design requirements for mechanical fastenings . 29
6.5.3 Design requirements for mechanical connecting elements . 29
6.5.4 Bearings . 29
6.6 Design requirements for signal generation . 30
6.6.1 General . 30
6.6.2 Design requirements for signal generation of optical Encoder(SR) . 30
6.6.3 Design requirements for signal generation of magnetic Encoder(SR) . 30
6.7 Design requirements for signal processing . 31
6.8 Design requirements for internal evaluation and signaling . 31
6.9 Design requirements for software . 31
6.10 Pre-setting . 31
6.11 Parameterization . 31
6.12 Design requirements for thermal immunity . 31
6.13 Design requirements for mechanical immunity . 31
6.14 Design requirements for integrated connection cables . 31
7 Information for use . 32
7.1 General . 32
7.2 Labels . 32
7.3 Information and instructions for safe application of an Encoder(SR) . 32
8 Verification and validation . 32

IEC 61800-5-3:2021 © IEC 2021 – 3 –
8.1 General . 32
8.2 Verification of hardware fault tolerance . 32
8.3 Additional verification for Encoder(SR) with sine and cosine output signals. 32
8.3.1 Verification of diagnostic measures for Encoder(SR) with sine and
cosine output signals with HFT = 0 . 32
8.3.2 Suitability for interpolation . 32
8.4 Qualitative FMEDA . 33
8.5 Quantification. 34
9 Test requirements . 34
9.1 General . 34
9.2 Planning of tests . 34
9.3 Functional testing . 34
9.4 Electromagnetic (EM) and electrical immunity testing . 34
9.4.1 Electrical tests . 34
9.4.2 Electromagnetic (EM) immunity testing . 35
9.5 Thermal immunity testing . 35
9.5.1 General . 35
9.5.2 Dry cold . 35
9.5.3 Dry heat . 35
9.5.4 Damp heat . 36
9.5.5 Temperature rise test . 36
9.6 Mechanical immunity testing . 36
9.6.1 Clearances and creepage distances . 36
9.6.2 Short-circuit testing of printed wiring boards . 36
9.6.3 Mechanical fastenings . 36
9.6.4 Mechanical connecting elements . 36
9.6.5 Vibration and shock test . 37
9.6.6 Mechanical properties of integrated connecting cables . 38
9.6.7 Testing the non-touchability . 38
9.6.8 Deformation testing . 38
9.7 Material tests . 38
9.8 Suitability of the components and materials used . 38
9.9 Contamination of solid measure . 39
9.10 Labels . 39
9.11 Instructions . 39
9.12 Test documentation . 39
10 Modification . 39
Annex A (informative) Types of Encoder(SR) . 40
Annex B (informative) Universal architecture of Encoder(SR) . 43
B.1 General . 43
B.2 The universal Encoder(SR) architecture . 43
Annex C (informative) Examples of suitable mechanical tests for rotary Encoder(SR) . 44
C.1 General . 44
C.2 Mechanical fastening of the Encoder(SR) . 44
C.2.1 Force-locked connection (e.g. by bolted joints) . 44
C.2.2 Form-locked connection (e.g. by feather key) . 44
C.3 Mechanical connecting elements of the Encoder(SR) – Stator coupling
(torque support) or shaft-rotor coupling . 45
C.3.1 General . 45

– 4 – IEC 61800-5-3:2021 © IEC 2021
C.3.2 Axial loads . 45
C.3.3 Radial loads . 45
Annex D (informative) Extended shock testing for rotary Encoder(SR) mounted to
motors . 47
D.1 General . 47
D.2 Pseudo-velocity shock-response spectrum (PVSRS) . 47
D.3 Verification of resilience . 47
D.4 Testing machine . 48
Annex E (informative) Dimensioning of clearances and creepage distances on printed

wiring boards – Example . 50
E.1 General . 50
E.2 Assumptions . 50
E.3 Application of IEC 61800-5-1:2007, 5.2.2.1 . 50
Annex F (normative) Information and instructions – Detailed list . 51
F.1 Overview. 51
F.2 Detailed list . 51
Annex G (informative) Encoder(SR) fault lists and fault exclusions . 54
Annex H (informative) Quantification . 58
H.1 General . 58
H.2 Safety architecture and safety-related block diagram . 58
H.3 Failure rates . 59
H.4 Failure rates at realistic working temperatures . 60
H.5 Quantitative FMEDA and assessment of diagnostic measures . 61
H.6 Estimation of the common cause factor β (only in case of redundancy) . 62
H.7 Estimation of the PFH . 62
H.8 Safe failure fraction (SFF) . 62
H.9 Determination of the quantitative SIL capability . 63
H.9.1 General . 63
H.9.2 SIL limit by architectural constraints . 63
H.9.3 SIL limit by PFH . 63
H.10 Additional considerations to comply with ISO 13849-1 . 64
H.10.1 General . 64
H.10.2 MTTF of a channel . 64
D
H.10.3 Determination of the quantitative category capability . 64
H.10.4 Determination of the quantitative PL-capability . 64
Annex I (informative) Digital processing of sine/cosine signals . 65
I.1 General . 65
I.2 Sampling of sine and cosine signals . 65
I.3 Consequences . 66
I.4 Measures to improve DC . 67
Annex J (informative) Single channel architecture with ideal fault detection . 68
J.1 General . 68
J.2 Ideal fault detection for Encoder(SR) with sine and cosine output signals . 68
Annex K (informative) Specifics for single channel incremental Encoder(SR) with sine

and cosine output signals . 70
K.1 General . 70
K.2 Single-fault tolerance . 70
K.3 Undetectable faults . 70

IEC 61800-5-3:2021 © IEC 2021 – 5 –
K.4 Fault detection (DC) . 70
Annex L (normative) Static analysis of signal evaluation and fault detection . 72
L.1 General . 72
L.2 Motivation for the analysis of signal evaluation and fault detection . 72
L.3 What does "static analysis of signal processing" mean? . 72
L.4 Standard test signals . 76
L.4.1 Make test signal available (step 1) . 76
L.4.2 Test signal 1 . 79
L.4.3 Test signal 2 . 79
L.4.4 Test signal 3 . 80
L.4.5 Test signal 4 . 80
L.4.6 Test signal 5 . 81
L.5 Simulation of signal processing to specification . 81
L.5.1 General . 81
L.5.2 Form differential signals (step 2). 83
L.5.3 Form square-wave signals to specification (Schmitt trigger, step 3) . 83
L.5.4 Perform specified diagnostics (step 4) . 83
L.6 Assessment of the signal processing specification . 84
L.6.1 General . 84
L.6.2 Assessment concept for the signal processing specification . 85
L.7 FMEDA Encoder(SR) for verification of the diagnostic coverage . 88
L.7.1 General . 88
L.7.2 Explanation of the problem . 88
L.7.3 Procedure for FMEDA . 90
L.8 List of variables used for performing static analysis . 92
L.9 MS Excel tool for performance of static analysis . 93
Annex M (informative) Aspects of diagnostic measures for obtaining incremental

position values . 94
M.1 General . 94
M.2 Obtaining position values from incremental signals . 94
M.3 Phase error of the sine and the cosine signals . 96
M.3.1 General . 96
M.3.2 Phase errors with absolute values < 90° . 96
M.3.3 Phase errors with absolute values > 90° . 99
M.4 Threshold errors of the square wave signal shapers . 100
M.4.1 General . 100
M.4.2 Asymmetric switching thresholds . 101
M.4.3 Unequal switching hysteresis at the square wave shaping for sine and
cosine . 101
Bibliography . 103

Figure 1 – Context of Encoder(SR) . 11
Figure 2 – Example of hardware architecture of Encoder(SR) with incremental and

absolute output signal . 28
Figure B.1 – Universal Encoder(SR) architecture . 43
Figure C.1 – Example of an additional ring for assembly with eccentricity x . 46
Figure D.1 – Sample shock and corresponding PVSRS on 4CP . 47
Figure D.2 – Testing machine . 48

– 6 – IEC 61800-5-3:2021 © IEC 2021
Figure I.1 – Digital sampling of sine and cosine signals – Hardware architecture,
example . 65
Figure I.2 – Lissajous figures of the sine and cosine signals A and B . 66
Figure L.1 – Static analysis concept . 73
Figure L.2 – Static analysis procedure (for one test signal) with variable

denominations . 76
Figure L.3 – Substitute circuit for Encoder(SR)’s outbound interface . 77
Figure L.4 – Example of a circuit for evaluation of the output signals and diagnostics
of Encoder(SR) faults . 82
Figure L.5 – Lissajous diagrams (representation of signal B over signal A) in two fault
cases . 90
Figure L.6 – Examples of the dual effect of a single component fault . 91
Figure M.1 – Obtaining position values from incremental signals . 95
Figure M.2 – Counting pulse generation, faultless case . 96
Figure M.3 – Counting pulse generation with a phase error of 20° . 97
Figure M.4 – Lissajous diagram with a phase error ∆ϕ = 20° . 98
Figure M.5 – Square-wave signal generation by means of a Schmitt trigger . 100
Figure M.6 – Counting pulse generation with asymmetric switching thresholds . 101
Figure M.7 – Counting pulse generation with unequal switching hysteresis . 102

Table 1 – List of terms . 13
Table 2 – Applicable subclauses of IEC 61800-5-2:2016 for Encoder(SR) and
respective modifications . 21
Table 3 – Applicable references of IEC 61800-5-1:2007 and IEC 61800-5-
1:2007/AMD1:2016 for Encoder(SR) and respective modifications . 23
Table A.1 – Types of Encoder(SR) . 40
Table B.1 – Function blocks of the universal Encoder(SR) architecture . 43
Table G.1 – Encoder(SR) – Mechanic fault list and fault exclusions . 55
Table G.2 – Faults and fault exclusions for the selection, mounting and operation of
rolling bearings . 56
Table G.3 – Factors influencing the malfunctioning of rolling bearings –
Considerations for selection, mounting and operation . 56
Table H.1 – Components for Encoder(SR) and their inclusion in quantification. 59

IEC 61800-5-3:2021 © IEC 2021 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ADJUSTABLE SPEED ELECTRICAL POWER DRIVE SYSTEMS –

Part 5-3: Safety requirements –
Functional, electrical and environmental requirements for encoders

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote 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 "IEC Publication(s)"). Their
preparation is entrusted to technical committees; any IEC National Committee interested 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 with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
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.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence 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 IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
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 61800-5-3 has been prepared by subcommittee 22G: Adjustable
speed electric power drive systems (PDS), of IEC technical committee 22: Power electronic
systems and equipment.
The text of this International Standard is based on the following documents:
FDIS Report on voting
22G/431/FDIS 22G/434/RVD
Full information on the voting for the approval of this International Standard can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
Terms in italics are defined in Clause 3.

– 8 – IEC 61800-5-3:2021 © IEC 2021
A list of all parts in the IEC 61800 series, published under the general title Adjustable speed
electrical power drive systems, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates that it
contains colours which are considered to be useful for the correct understanding of its
contents. Users should therefore print this document using a colour printer.

IEC 61800-5-3:2021 © IEC 2021 – 9 –
INTRODUCTION
As a result of automation, demand for increased production and reduced operator physical
effort, control systems of machinery and plant items play an increasing role in the achievement
of overall safety. These control systems increasingly employ complex
electrical/electronic/programmable electronic devices and systems.
Prominent amongst these devices and systems are encoder which are for example applied to
measure angle and position of machine parts for use in safety-related applications
(Encoder(SR)). Based on the Encoder(SR)’s output signals, PDS(SR) or other evaluation units
calculate for example speed, acceleration, absolute position, etc., to perform their safety sub-
functions SLS, SLA, SLP and others (see IEC 61800-5-2:2016, Clause 4). The signal
processing necessary to perform some of these safety sub-functions may also be included in
the Encoder(SR).
Examples of industrial applications are:
• machine tools, robots, production test equipment, test benches;
• papermaking machines, textile production machines, calendars in the rubber industry;
• plastics processing lines, chemicals or metal production lines, rolling-mills;
• cement crushing machines, cement kilns, mixers, centrifuges, extrusion machines;
• drilling machines;
• conveyors, materials handling machines, hoisting equipment (cranes, gantries, etc.);
• pumps, fans, etc.
This document can also be used as a reference for developers using Encoder(SR) for other
applications, for example in wind power plants.
Users of this document should be aware that some type C standards for machinery currently
refer to ISO 13849-1 for safety-related control systems. In this case, Encoder(SR)
manufacturers may be requested to provide further information (e.g. category and performance
level PL) to facilitate the integration of an Encoder(SR) into the safety-related control systems
of such machinery. This has been considered during development of this document and
corresponding indications are included where appropriate.
NOTE "Type C standards" are defined in ISO 12100 [1] as machine safety standards dealing with detailed safety
requirements for a particular machine or group of machines.
There are many situations where control systems that incorporate Encoder(SR) are employed,
for example as part of safety measures that have been provided to achieve risk reduction. A
typical case is reducing the speed during start-up in order to protect personnel from hazards
arising by unexpected fast movements of machine parts. This document gives a methodology
to identify the contribution made by an Encoder(SR) to identified safety sub-functions and to
enable the appropriate design of the Encoder(SR) and verification that it achieves the required
performance.
Measures are given to co-ordinate the safety performance of the Encoder(SR) with the intended
risk reduction taking into account the probabilities and consequences of its random and
systematic faults.
– 10 – IEC 61800-5-3:2021 © IEC 2021
ADJUSTABLE SPEED ELECTRICAL POWER DRIVE SYSTEMS –

Part 5-3: Safety requirements –
Functional, electrical and environmental requirements for encoders

1 Scope
This part of IEC 61800, which is a product standard, specifies requirements and makes
recommendations for the design and development, integration and validation of safety-related
encoder (Encoder(SR)) in terms of their functional safety considerations, electrical safety and
environmental conditions. It applies to Encoder(SR), being sensors as part of a PDS(SR).
NOTE 1 The term "integration" refers to the Encoder(SR) itself, not to its incorporation into the safety-related
application.
This document can also be referred to and used for Encoder(SR) in any other safety-related
application, for example safety-related position monitoring.
NOTE 2 This document specifies only complementary functional safety, electrical safety and environmental condition
requirements that are not clearly provided by other parts of the IEC 61800 series.
This document is applicable where functional safety of an encoder is claimed and the
Encoder(SR) is operating mainly in the high demand or continuous mode.
NOTE
...