Safety of machinery - Safety-related sensors used for the protection of persons

IEC TS 62998-1:2019 gives requirements for the development and integration of safety related sensors (SRS) and safety related sensor systems (SRSS) used for protection of persons with special attention to systematic capabilities.
This generic standard only applies if
– protection of persons is to be performed by using sensors, and
– standards for functional safety of electrical control systems address sensor(s) as subsystem or subsystem element, and
– product specific sensor standards (e.g. IEC 61496 (all parts), IEC 60947-5-2) do not contain all necessary provisions, or product specific sensor standards are not developed.
The approach of examination of systematic capabilities by using different safety related sensor standards is described in Annex A.
The requirements and methods within this document are limited to the purpose of protection of persons
– by detection of potentially hazardous objects,
– by detection of a body, parts of a body and objects associated to parts of a body entering a hazardous area, or
– by classification respective discrimination of these against other objects.
Special attention is given to the sensing function and dependability of the detection capability. Environmental influences and tests for indoor and outdoor use are defined which influence the sensing function and dependability of the detection capability.
IEC TS 62998-1:2019 can be relevant to applications other than those for the protection of persons in industries, for example, for the protection of persons in public like agriculture or metro stations.
IEC TS 62998-1:2019 does not consider and address proven in use (e.g. processes or elements) as done in IEC 61508-2.

General Information

Status
Published
Publication Date
01-May-2019
Current Stage
PPUB - Publication issued
Completion Date
02-May-2019
Ref Project

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IEC TS 62998-1
Edition 1.0 2019-05
TECHNICAL
SPECIFICATION
colour
inside
Safety of machinery –
Safety-related sensors used for the protection of persons
IEC TS 62998-1:2019-05(en)
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---------------------- Page: 2 ----------------------
IEC TS 62998-1
Edition 1.0 2019-05
TECHNICAL
SPECIFICATION
colour
inside
Safety of machinery –
Safety-related sensors used for the protection of persons
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 13.110; 21.020 ISBN 978-2-8322-6819-3

Warning! Make sure that you obtained this publication from an authorized distributor.

® Registered trademark of the International Electrotechnical Commission
---------------------- Page: 3 ----------------------
– 2 – IEC TS 62998-1:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 6

INTRODUCTION ..................................................................................................................... 8

1 Scope .............................................................................................................................. 9

2 Normative references .................................................................................................... 10

3 Terms and definitions .................................................................................................... 10

3.1 Characteristics and performance criteria ............................................................... 11

3.2 Dependability ........................................................................................................ 12

3.3 Procedures and architectural deliberations ........................................................... 14

3.4 Terms related to system ........................................................................................ 16

3.5 Fusion................................................................................................................... 18

3.6 Safety related information ..................................................................................... 18

3.7 Test ...................................................................................................................... 20

3.8 User groups .......................................................................................................... 22

3.9 Verification and validation ..................................................................................... 22

4 Lifecycle and interconnection to safety-related electrical control systems (SCS) ............ 24

4.1 General ................................................................................................................. 24

4.2 Hazard and risk analysis ....................................................................................... 26

4.2.1 General ......................................................................................................... 26

4.2.2 Hazard caused by SRS/SRSS........................................................................ 27

4.2.3 Required SRS/SRSS performance class ........................................................ 28

4.3 Correspondence SRS/SRSS performance class .................................................... 28

5 Design and development phase ..................................................................................... 29

5.1 General ................................................................................................................. 29

5.2 SRS/SRSS functions ............................................................................................. 29

5.3 Design analysis..................................................................................................... 30

5.4 Simulation ............................................................................................................. 30

5.5 Sensing zone(s) .................................................................................................... 31

5.6 Safety related zone ............................................................................................... 31

5.7 Automation related zone ....................................................................................... 31

5.8 Detection capability and dependability .................................................................. 31

5.8.1 General ......................................................................................................... 31

5.8.2 Object classes and physical properties .......................................................... 32

5.8.3 Environmental influences ............................................................................... 33

5.9 User interface ....................................................................................................... 37

5.9.1 General ......................................................................................................... 37

5.9.2 Mounting ....................................................................................................... 37

5.9.3 Safety related information .............................................................................. 37

6 Integration and installation phase .................................................................................. 40

6.1 General ................................................................................................................. 40

6.2 Fusion of SRS into an SRSS ................................................................................. 40

6.2.1 General ......................................................................................................... 40

6.2.2 Limits of use after fusion ................................................................................ 41

6.2.3 Detection capability after fusion ..................................................................... 41

6.2.4 Sensing zone(s) after fusion .......................................................................... 42

6.2.5 Dependability under environmental condition after fusion .............................. 42

6.2.6 Safety related information after fusion ........................................................... 42

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IEC TS 62998-1:2019 © IEC 2019 – 3 –

6.2.7 SRSS performance class after fusion ............................................................. 43

6.2.8 Response time after fusion ............................................................................ 44

6.2.9 Verification and validation after fusion ........................................................... 44

6.3 Calibration at user side ......................................................................................... 44

6.3.1 General ......................................................................................................... 44

6.3.2 Calibration procedure and equipment ............................................................ 45

6.3.3 Verification and validation of calibration ......................................................... 45

7 Operation, maintenance and modification phases .......................................................... 45

8 Verification and validation .............................................................................................. 46

8.1 General ................................................................................................................. 46

8.2 Verification of an SRS/SRSS ................................................................................ 46

8.3 Validation of an SRS/SRSS .................................................................................. 47

8.4 Analysis ................................................................................................................ 48

8.5 Test ...................................................................................................................... 49

8.5.1 General ......................................................................................................... 49

8.5.2 Test classification .......................................................................................... 49

8.5.3 Test method and test setup ........................................................................... 50

8.5.4 Test piece ...................................................................................................... 51

8.5.5 Test plan and test results .............................................................................. 51

9 Information for use ......................................................................................................... 52

Annex A (informative) Examination of systematic capabilities ............................................. 54

Annex B (informative) User groups ...................................................................................... 55

B.1 User groups of SRS/SRSS and groups addressed by this document ..................... 55

B.2 User groups addressed by fusion .......................................................................... 55

Annex C (informative) Functional decomposition and/or integration .................................... 58

Annex D (normative) Generation and application of simulation models ................................. 59

D.1 General ................................................................................................................. 59

D.2 Recommendations for use..................................................................................... 59

D.3 Simulation objectives and measures to achieve them ............................................ 59

D.4 Verification............................................................................................................ 62

Annex E (informative) Child properties and behaviour .......................................................... 64

E.1 General ................................................................................................................. 64

E.2 Sizes of parts of body ........................................................................................... 64

Annex F (informative) Environmental influences ................................................................... 68

F.1 General ................................................................................................................. 68

F.2 Example 1 for application of environmental influences .......................................... 68

F.3 Example 2 for application of environmental influences .......................................... 70

Annex G (informative) Faults, failures and influences resulting in a loss of SRS/SRSS

safety related function........................................................................................................... 71

G.1 General ................................................................................................................. 71

G.2 Failure to danger .................................................................................................. 74

G.3 Normal operation .................................................................................................. 75

G.4 Signal to initiate the fault reaction function and confidence information as

part of safety related information ........................................................................... 75

Annex H (informative) Test aspects ..................................................................................... 77

H.1 General ................................................................................................................. 77

H.2 Mechanical influence test ...................................................................................... 77

Annex I (informative) Examples of functions, safety related information and fusion ............. 81

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– 4 – IEC TS 62998-1:2019 © IEC 2019

I.1 Example of functions ............................................................................................. 81

I.2 Example of safety related information ................................................................... 82

I.3 Example of fusion ................................................................................................. 83

Bibliography .......................................................................................................................... 87

Figure 1 – Measurement accuracy and measurement uncertainty ......................................... 12

Figure 2 – Example 1 of SRS architecture ............................................................................. 24

Figure 3 – Example 2 of SRS architecture ............................................................................. 25

Figure 4 –Example of SRSS architecture .............................................................................. 25

Figure 5 – Interconnection of an SRS/SRSS into hazard and risk analysis ............................ 27

Figure 6 – Safety related information of an SRS/SRSS ......................................................... 38

Figure A.1 – Example for examination of systematic capabilities using safety related

sensor standards .................................................................................................................. 54

Figure C.1 – Interconnection of functions and objects ........................................................... 58

Figure C.2 – Example of functions performed in an SRSS ..................................................... 58

Figure D.1 – Verification process .......................................................................................... 62

Figure E.1 – Body height children ......................................................................................... 65

Figure E.2 – Chest depth children ......................................................................................... 66

Figure E.3 – Head width children .......................................................................................... 66

Figure E.4 – Head length children ......................................................................................... 67

Figure G.1 – Combination of faults, failures or errors resulting in additional risk

throughloss of safety function or bypassing ........................................................................... 72

Figure G.2 – Analysis of systematic capabilities during design and development to

prevent systematic faults resulting in failure to danger .......................................................... 73

Figure G.3 – Mode of action for systematic fault resulting in fault reaction function ............... 76

Figure G.4 – Mode of action for errors resulting in appropriate confidence information .......... 76

Figure I.1 – Example of SRS applied on driveway intersection .............................................. 81

Figure I.2 – Example of SRS/SRSS providing decision and confidence information .............. 82

Figure I.3 – Example of SRS/SRSS providing measurement and confidence

information ............................................................................................................................ 83

Figure I.4 – First dxample of fusion of 2 SRS into an SRSS with combined sensing

zones .................................................................................................................................... 84

Figure I.5 – Fusion of SRS safety related information .......................................................... 84

Figure I.6 – Approach of verification and validation based on SRS Information for use

and SRSS Safety Requirement specification ......................................................................... 85

Figure I.7 – Second example of fusion of 2 SRS into an SRSS with combined sensing

zones .................................................................................................................................... 86

Table 1 – Correspondence between level of safety performance and minimum

required SRS/SRSS performance class ................................................................................ 29

Table 2 – Functions of an SRS/SRSS as applicable .............................................................. 30

Table 4 – Limits for failure to danger condition (loss of the detection capability) due to

environmental interference for high demand mode ................................................................ 35

Table 5 – Minimum required coverage probability/decision probability at high

demand rate ......................................................................................................................... 39

Table 6 – Maximum applicable SRSS performance class after fusion using two SRS ............ 44

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IEC TS 62998-1:2019 © IEC 2019 – 5 –

Table 7 – Means to be used for evaluation of verification measures and verification

results .................................................................................................................................. 47

Table 8 – Overview of information for use to be provided ...................................................... 52

Table B.1 – Roles and task of addressed user groups ........................................................... 55

Table B.2 – Addressed user groups for different integration types using sensing unit,

SRS/ SRSS as element or SRS as subsystem ...................................................................... 56

Table D.1 – Simulation objectives and measures for SRS/SRSS of low complexity .............. 60

Table D.2 – Simulation objectives and measures for SRS/SRSS of high complexity ............. 61

Table E.1– Body height children ........................................................................................... 64

Table E.2 – Chest depth children .......................................................................................... 65

Table E.3 – Head width children ........................................................................................... 66

Table E.4 – Head length children .......................................................................................... 67

Table F.1 – Example 1 of environmental influence and classes according to

IEC 60721-3-5 ...................................................................................................................... 69

Table F.2 – Example 2 of environmental influence and classes according to

IEC 60721-3-3 ...................................................................................................................... 70

Table G.1 – Demand rates used for the calculation of Table G.2 values ................................ 74

Table G.2 – Limits for failure to danger condition (loss of the detection capability) due

to environmental influence for high demand mode ................................................................ 74

Table H.1 – Example of test plan and test result for mechanical influence test ...................... 78

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– 6 – IEC TS 62998-1:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF MACHINERY –
Safety-related sensors used for the protection of persons
FOREWORD

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The main task of IEC technical committees is to prepare International Standards. In

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Specification when

• the required support cannot be obtained for the publication of an International Standard,

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• the subject is still under technical development or where, for any other reason, there is the

future but no immediate possibility of an agreement on an International Standard.

Technical Specifications are subject to review within three years of publication to decide

whether they can be transformed into International Standards.

IEC TS 62998-1, which is a Technical Specification, has been prepared by IEC technical

committee TC 44: Safety of machinery – Electrotechnical aspects.
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IEC TS 62998-1:2019 © IEC 2019 – 7 –
The text of this Technical Specification is based on the following documents:
Draft TS Report on voting
44/826/DTS 44/839A/RVDTS

Full information on the voting for the approval of this Technical Specification 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.

A list of all parts in the IEC 62998 series, published under the general title Safety of

machinery, 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.
A bilingual version of this publication may be issued at a later date.

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Users should therefore print this document using a colour printer.
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– 8 – IEC TS 62998-1:2019 © IEC 2019
INTRODUCTION

Safety related sensors are applied to machinery presenting a risk of personal injury. They

provide protection by causing the machine to revert to a safe condition before a person can

be placed in a hazardous situation.

IEC 61496 (all parts) provides design and performance requirements of electro-sensitive

protective equipment (ESPE). It gives a clear but limited guideline for

– specific sensor technologies (like optical sensors) or sensing functions (like capability to

detect a specified object);
– typical conditions representing indoor use in industrial environment;

– detection of objects representing parts of body of adults using the properties geometry

and reflectivity;

– design, functional requirements and tests in accordance with ESPE specific safety

performance classification in types (2,3 and 4).

Autonomous systems like automated guided vehicles ( AGV), service robotics or human

machine interaction in industries show an increasing demand, for example in
– new sensor technologies (e.g. radar, ultrasonic sensors),

– new kind of sensor functions (e.g. classification of objects, position of an object), and

– combination of different sensor technologies in a sensor system.

Sensor manufacturers or integrators use in such cases generic functional safety standards

as guideline for the safety related product design. Generic functional safety standards like

IEC 61508 (all parts) or sector specific machinery standards like IEC 62061 or ISO 13849 (all

parts) are general and product design can be carried out without inappropriate limitations.

Applying these standards would require a dedicated analysis of systematic capabilities of a

sensor or sensor system (e.g. dependability of the sensing function under tolerance

conditions and environmental influences). There is not enough guidance given in these

standards to prevent design failures or insufficient capability to detect the specified object in

certain environmental conditions. This can result in an intolerable risk for persons.

This document fills the gap for the examination of systematic capabilities between d es i gn

specific sensor standards and generic functional safety standards of electrical,
electronic or programmable electronic control systems.
NOTE 1 Examples for the ex
...

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