SIST-TS CLC/TS 61496-2:2006

Safety of machinery - Electro-sensitive protective equipment -- Part 2: Particular requirements for equipment using active opto-electronic protective devices (AOPDs)

This part of IEC 61496 specifies requirements for the design, construction and testing of electro-sensitive protective equipment (ESPE) designed specifically to detect persons as part of a safety-related system, employing active opto-electronic protective devices (AOPDs) for the sensing function. Special attention is directed to features which ensure that an appropriate safety-related performance is achieved. An ESPE may include optional safety-related functions, the requirements for which are given in Annex A of IEC 61946-1 and of this part. This part does not specify the dimensions or configurations of the detection zone and its disposition in relation to hazardous parts for any particular application, nor what constitutes a hazardous state of any machine. It is restricted to the functioning of the ESPE and how it interfaces with the machine. Excluded from this part are AOPDs employing radiation at wavelengths outside the range 400 nm to 1500 nm. This part may be relevant to applications other than those for the protection of persons, for example, the protection of machinery or products from mechanical damage. In those applications, additional requirements may be necessary, for example, when the materials that are to be recognized by the sensing function have different properties from those of persons. This part does not deal with EMC emission requirements. This Technical Specification supersedes CLC/TS 61496-2:2003. Tis Technical Specification includes the following technical changes with respect to LC/TS 61496-2:2003: a)Requirements have been corrected and made easier to understand. B)Test procedures have been revised to make them easier to perform and to improve repeatability. C)uidance is provided for the evaluation and verification of AOPDs using design techniques for which he test procedures of this part are not appropriate.

Sicherheit von Maschinen - Berührungslos wirkende Schutzeinrichtungen -- Teil 2: Besondere Anforderungen an Einrichtungen, welche nach dem aktiven opto-elektronischen Prinzip arbeiten

Sécurité des machines - Equipement de protection électrosensible -- Partie 2: Exigences particulières à un équipement utilisant des dispositifs protecteurs optoélectroniques actifs (AOPD)

définit les exigences de conception, de construction et d'essai d'équipements de protection électrosensibles (ESPE) conçus spécialement pour détecter des personnes, comme partie d'un système relatif à la sécurité, utilisant des dispositifs protecteurs optoélectroniques actifs (AOPD) pour la fonction de détection. Une attention particulière est portée sur les caractéristiques assurant qu'une performance relative à la sécurité appropriée est atteinte. Un ESPE peut comporter des fonctions relatives à la sécurité optionnelles; les exigences pour ces fonctions sont données aux Annexes A de la CEI 61946-1 et de la présente Partie.

Varnost strojev – Električno občutljiva zaščitna oprema – 2. del: Posebne zahteve za opremo, ki uporablja aktivne optoelektronske zaščitne elemente (IEC 61496-2:2006)

General Information

• Status: Withdrawn
• Publication Date: 30-Sep-2006
• Withdrawal Date: 22-Oct-2015
• ICS: 13.110 - Safety of machinery
• ICS: 31.260 - Optoelectronics. Laser equipment
• Technical Committee: MOV - Measuring equipment for electromagnetic quantities
• Current Stage: 9900 - Withdrawal (Adopted Project)
• Start Date: 22-Oct-2015
• Due Date: 14-Nov-2015
• Completion Date: 23-Oct-2015
• Directive: 98/37/EC - Machinery
• Ref Project: CLC/TS 61496-2:2006 - Safety of machinery - Electro-sensitive protective equipment - Part 2: Particular requirements for equipment using active opto-electronic protective devices (AOPDs)

Relations

• Revised: SIST EN 61496-2:2014 - Safety of machinery - Electro-sensitive protective equipment - Part 2: Particular requirements for equipment using active opto-electronic protective devices (AOPDs)
• Effective Date: 06-May-2014
• Replaces: SIST-TS CLC/TS 61496-2:2005 - Safety of machinery - Electro-sensitive protective equipment -- Part 2: Particular requirements for equipment using active opto-electronic protective devices (AOPD)
• Effective Date: 13-May-2010
• Replaces: SIST-TS CLC/TS 61496-2:2005 - Safety of machinery - Electro-sensitive protective equipment -- Part 2: Particular requirements for equipment using active opto-electronic protective devices (AOPD)
• Effective Date: 29-Jan-2023

Standards Content (Sample)

SLOVENSKI SIST-TS CLC/TS 61496-2:2006

STANDARD
oct 2006
Varnost strojev – Električno občutljiva zaščitna oprema – 2. del: Posebne
zahteve za opremo, ki uporablja aktivne optoelektronske zaščitne elemente
(IEC 61496-2:2006)
Safety of machinery - Electro-sensitive protective equipment – Part 2: Particular
requirements for equipment using active opto-electronic protective devices
(AOPDs) (IEC 61496-2:2006)
ICS 13.110; 31.260 Referenčna številka
SIST-TS CLC/TS 61496-2:2006(en)
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

---------------------- Page: 1 ----------------------

TECHNICAL SPECIFICATION
CLC/TS 61496-2

SPÉCIFICATION TECHNIQUE
July 2006
TECHNISCHE SPEZIFIKATION

ICS 13.110.; 29.260.99 Supersedes CLC/TS 61496-2:2003


English version


Safety of machinery -
Electro-sensitive protective equipment
Part 2: Particular requirements for equipment using
active opto-electronic protective devices (AOPDs)
(IEC 61496-2:2006)


Sécurité des machines -  Sicherheit von Maschinen -
Equipement de protection électrosensible Berührungslos wirkende
Partie 2: Exigences particulières à Schutzeinrichtungen
un équipement utilisant des dispositifs Teil 2: Besondere Anforderungen an
protecteurs optoélectroniques actifs Einrichtungen, welche nach dem aktiven
(AOPD) opto-elektronischen Prinzip arbeiten
(CEI 61496-2:2006) (IEC 61496-2:2006)





This Technical Specification was approved by CENELEC on 2006-06-01.

CENELEC members are required to announce the existence of this TS in the same way as for an EN and to
make the TS available promptly at national level in an appropriate form. It is permissible to keep conflicting
national standards in force.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.



CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung

Central Secretariat: rue de Stassart 35, B - 1050 Brussels


© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. CLC/TS 61496-2:2006 E

---------------------- Page: 2 ----------------------

CLC/TS 61496-2:2006 - 2 -
Foreword
The text of document 44/500/FDIS, future edition 2 of IEC 61496-2, prepared by IEC TC 44, Safety of
machinery - Electrotechnical aspects, in collaboration with the Technical Committee CENELEC TC 44X,
Safety of machinery: electrotechnical aspects, was submitted to the IEC-CENELEC parallel vote and was
approved by CENELEC as CLC/TS 61496-2 on 2006-06-01.
This Technical Specification supersedes CLC/TS 61496-2:2003.
This Technical Specification includes the following technical changes with respect to
CLC/TS 61496-2:2003:
a) Requirements have been corrected and made easier to understand.
b) Test procedures have been revised to make them easier to perform and to improve repeatability.
c) Guidance is provided for the evaluation and verification of AOPDs using design techniques for which
the test procedures of this part are not appropriate.
This Technical Specification is to be used in conjunction with EN 61496-1:2004.
The following date was fixed:
– latest date by which the existence of the CLC/TS has to be
announced at national level (doa) 2006-12-01
Annex ZA has been added by CENELEC.
__________
Endorsement notice
The text of the International Standard IEC 61496-2:2006 was approved by CENELEC as a Technical
Specification without any modification.
__________

---------------------- Page: 3 ----------------------

- 3 - CLC/TS 61496-2:2006
Annex ZA
(normative)

Normative references to international publications
with their corresponding European publications

The following referenced documents are indispensable for the application 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  When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD
applies.


Publication Year Title EN/HD Year

1) 2)
IEC 60825-1 - Safety of laser products EN 60825-1 1994
Part 1: Equipment classification, requirements + corr. February 1995
and user's guide + A11 1996


IEC/TS 62046 2004 Safety of machinery - Application of protective CLC/TS 62046 2005
equipment to detect the presence of persons


ISO 13855 2002 Safety of machinery - Positioning of protective - -
equipment with respect to the approach
speeds of parts of the human body


- - High-visibility warning clothing for EN 471 2003
professional use - Test methods and
requirements




1)
Undated reference.
2)
Valid edition at date of issue.

---------------------- Page: 4 ----------------------

NORME CEI
INTERNATIONALE
IEC



61496-2
INTERNATIONAL


Deuxième édition
STANDARD

Second edition

2006-04


Sécurité des machines –
Equipement de protection électrosensible –
Partie 2:
Exigences particulières à un équipement
utilisant des dispositifs protecteurs
optoélectroniques actifs (AOPD)

Safety of machinery –
Electro-sensitive protective equipment –
Part 2:
Particular requirements for equipment
using active opto-electronic protective
devices (AOPDs)

 IEC 2006 Droits de reproduction réservés  Copyright - all rights reserved
Aucune partie de cette publication ne peut être reproduite ni No part of this publication may be reproduced or utilized in any
utilisée sous quelque forme que ce soit et par aucun procédé, form or by any means, electronic or mechanical, including
électronique ou mécanique, y compris la photocopie et les photocopying and microfilm, without permission in writing from
microfilms, sans l'accord écrit de l'éditeur. the publisher.
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
CODE PRIX
X
PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

---------------------- Page: 5 ----------------------

61496-2  IEC:2006 – 3 –
CONTENTS
FOREWORD.7
INTRODUCTION.11

1 Scope.13
2 Normative references .13
3 Terms and definitions .15
4 Functional, design and environmental requirements .17
4.1 Functional requirements .17
4.2 Design requirements .23
4.3 Environmental requirements .27
5 Testing .27
5.1 General .27
5.2 Functional tests .29
6 Marking for identification and safe use.61
6.1 General .61
7 Accompanying documents .63

Annex A (normative) Optional functions of the ESPE .65
Annex B (normative) Catalogue of single faults affecting the electrical equipment of
the ESPE, to be applied as specified in 5.3.67
Annex C (normative) Verifying effective aperture angle using the prism method.69
Annex D (normative) Verifying optical performance using the mirror method and
misalignment test.77
Annex E (informative) AOPD detection capability based on complete obscuration.85

Bibliography.87

Index .89

Figure 1 – Limit area for the protection against the risk of beam bypass .19
Figure 2 – Measurement of the effective aperture angle (EAA).21
Figure 3 – Test piece at 45° .31
Figure 4 – Test piece at 90° .31
Figure 5 – Verifying sensing function by moving the test piece (TP) through the
detection zone near the emitter, near the receiver/retro-reflector target and at the
midpoint.33
Figure 6 – Analysis and tests of AOPDs – Flow chart.39
Figure 7 – Measuring method for EAA (direction) .43
Figure 8 – Light interference test – Direct method.47
Figure 9 – Light interference test – Test set-up with halogen light source .49
Figure 10 – Light interference test – Test set-up with fluorescent light source.51

---------------------- Page: 6 ----------------------

61496-2  IEC:2006 – 5 –
Figure 11 – Light interference test – Test set-up with xenon flashing beacon .53
Figure 12 – Light interference test – Test set-up with strobe lamp.55
Figure D.1 – Prism test to measure EAA of each beam .71
Figure D.2 – EAA test using prism .73
Figure D.3 – Design calculations for a wedge prism .75
Figure E.1 – AOPD misalignment.81
Figure E.2 – Extraneous reflections .83
Figure F.1 – Determination of the minimum detection capability.85

Table E.1 – Maximum permissible angle of misalignment (in degrees) for a
type 2 ESPE depending on the dimensions of the light curtain .77
Table E.2 – Maximum permissible angle of misalignment (in degrees) for a
type 4 ESPE depending on the dimensions of the light curtain .79

---------------------- Page: 7 ----------------------

61496-2  IEC:2006 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________

SAFETY OF MACHINERY –
ELECTRO-SENSITIVE PROTECTIVE EQUIPMENT –

Part 2: Particular requirements for equipment using active
opto-electronic protective devices (AOPDs)


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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any
equipment declared to be in conformity with an IEC Publication.
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 61496-2 has been prepared by IEC technical committee 44: Safety
of machinery – Electrotechnical aspects, in collaboration with CENELEC technical committee
44X: Safety of machinery – Electrotechnical aspects.
This second edition cancels and replaces the first edition published in 1997 and constitutes a
technical revision.
This edition includes the following technical changes with respect to the previous edition:
a) Requirements have been corrected and made easier to understand.
b) Test procedures have been revised to make them easier to perform and to improve
repeatability.
c) Guidance is provided for the evaluation and verification of AOPDs using design
techniques for which the test procedures of this part are not appropriate.

---------------------- Page: 8 ----------------------

61496-2  IEC:2006 – 9 –
This standard has the status of a product family standard and may be used as a normative
reference in a dedicated product standard for the safety of machinery.
This standard is to be used in conjunction with IEC 61496-1 (2004).
The text of this standard is based on the following documents:
FDIS Report on voting
44/500/FDIS 44/508/RVD

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
IEC 61946 consists of the following parts, under the general title: Safety of machinery –
Electro-sensitive protective equipment
Part 1: General requirements and tests
Part 2: Particular requirements for equipment using active opto-electronic protective
devices (AOPDs)
Part 3: Particular requirements for Active Opto-electronic Protective Devices responsive to
Diffuse Reflection (AOPDDR)
The committee has decided that the contents of this publication will remain unchanged until
the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in the
data related to the specific publication. At this date, the publication will be
• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.

---------------------- Page: 9 ----------------------

61496-2  IEC:2006 – 11 –
INTRODUCTION
Electro-sensitive protective equipment (ESPE) is applied to machinery that presents a risk of
personal injury. It provides protection by causing the machine to revert to a safe condition
before a person can be placed in a hazardous situation.
This part of IEC 61496 provides particular requirements for the design, construction and
testing of electro-sensitive protective equipment (ESPE) for the safeguarding of machinery,
employing active opto-electronic protective devices (AOPDs) for the sensing function.
This part supplements or modifies the corresponding clauses in IEC 61496-1.
Where a particular clause or subclause of Part 1 is not mentioned in this Part 2, that clause or
subclause applies as far as is reasonable. Where this part states "addition", "modification" or
"replacement", the relevant text of Part 1 is to be adapted accordingly.
Each type of machine presents its own particular hazards, and it is not the purpose of this
standard to recommend the manner of application of the ESPE to any particular machine. The
application of the ESPE should be a matter for agreement between the equipment supplier,
the machine user and the enforcing authority; in this context, attention is drawn to the relevant
guidance established internationally, for example, ISO 12100.

---------------------- Page: 10 ----------------------

61496-2  IEC:2006 – 13 –
SAFETY OF MACHINERY –
ELECTRO-SENSITIVE PROTECTIVE EQUIPMENT –

Part 2: Particular requirements for equipment using active
opto-electronic protective devices (AOPDs)



1 Scope
This clause of Part 1 is replaced by the following:
This part of IEC 61496 specifies requirements for the design, construction and testing of
electro-sensitive protective equipment (ESPE) designed specifically to detect persons as part
of a safety-related system, employing active opto-electronic protective devices (AOPDs) for
the sensing function. Special attention is directed to features which ensure that an appropriate
safety-related performance is achieved. An ESPE may include optional safety-related
functions, the requirements for which are given in Annex A of IEC 61946-1 and of this part.
This part does not specify the dimensions or configurations of the detection zone and its
disposition in relation to hazardous parts for any particular application, nor what constitutes a
hazardous state of any machine. It is restricted to the functioning of the ESPE and how it
interfaces with the machine.
Excluded from this part are AOPDs employing radiation at wavelengths outside the range
400 nm to 1500 nm.
This part may be relevant to applications other than those for the protection of persons, for
example, the protection of machinery or products from mechanical damage. In those
applications, additional requirements may be necessary, for example, when the materials that
are to be recognized by the sensing function have different properties from those of persons.
This part does not deal with EMC emission requirements.
2 Normative references
This clause of Part 1 is applicable except as follows:
Additional references:
IEC 60825-1, Safety of laser products – Part 1: Equipment classification, requirements and
user's guide
IEC 62046:2004, Safety of machinery – Application of protective equipment to detect the
presence of persons
ISO 13855:2002, Safety of machinery – Positioning of protective equipment with respect to
the approach speeds of parts of the human body
EN 471:2003, High-visibility warning clothing for professional use – Test methods and
requirements.

---------------------- Page: 11 ----------------------

61496-2  IEC:2006 – 15 –
3 Terms and definitions
NOTE At the end of this standard there is an index which lists, in alphabetical order, the terms and acronyms
defined in Clause 3 and indicates where they are used in the text.
This clause of Part 1 is applicable except as follows:
Additional definitions:
3.201
active opto-electronic protective device (AOPD)
device whose sensing function is performed by opto-electronic emitting and receiving
elements detecting the interruption of optical radiations generated, within the device, by an
opaque object present in the specified detection zone (or for a light beam device, on the axis
of the light beam)
3.202
beam centre-line
optical path joining the optical centre of an emitting element to the optical centre of the
corresponding receiving element that is intended to respond to light from that emitting element
during normal operation
NOTE 1 The optical axis of a light beam is not always on the beam centre-line.
NOTE 2 Physical displacement of the beam centre-line may occur as a consequence of normal operation (for
example, by the use of a motor-driven mirror).
NOTE 3 For an AOPD that operates on a retro-reflective technique, the optical path is defined by the retro-
reflector target together with the emitting and receiving elements.
3.203
effective aperture angle (EAA)
maximum angle of deviation from the optical alignment of the emitting element(s) and the
receiving element(s) within which the AOPD continues in normal operation
3.204
light beam device
single light beam device or a multiple light beam device
– single light beam device: AOPD comprising one emitting element and one receiving
element, where a detection zone is not specified by the supplier;
– multiple light beam device: AOPD comprising multiple emitting elements and
corresponding receiving elements, and where a detection zone is not specified by the
supplier
3.205
light curtain
AOPD comprising an integrated assembly of one or more emitting element(s) and one or more
receiving element(s) forming a detection zone with a detection capability specified by the
supplier
NOTE A light curtain with a large detection capability is sometimes referred to as a light grid.
3.206
test piece
opaque cylindrical element used to verify the detection capability of the AOPD
3.207
monitored blanking
configuration of the detection capability and/or detection zone in such a way that the presence
of an object(s) within a defined part of the detection zone will not cause an OFF-state of the
OSSD(s) but the absence (or, in some cases, a change in size or location) of the object will
cause the OSSD(s) to go to the OFF-state

---------------------- Page: 12 ----------------------

61496-2  IEC:2006 – 17 –
Replacement:
3.3
detection capability
dimension representing the diameter of the test piece which:
– for a light curtain, will actuate the sensing device when placed in the detection zone;
– for a single light beam device, will actuate the sensing device when placed in the beam
centre-line;
– for a multiple light beam device, will actuate the sensing device when placed in any beam
centre-line
NOTE Can also be used to mean the ability to detect a test piece of the specified diameter.
4 Functional, design and environmental requirements
This clause of Part 1 is applicable except as follows:
4.1 Functional requirements
4.1.2 Sensing function
Replacement:
4.1.2.1 General
The sensing function shall be effective over the detection zone specified by the supplier. No
adjustment of the detection zone, detection capability or blanking function shall be possible
without the use of a key, key-word or tool.
The sensing device of a light curtain shall be actuated and the OSSD(s) shall go to the OFF-
state when a test piece in accordance with 4.2.13 is placed anywhere within the detection
zone either static (at any angle) or moving (with the axis of the cylinder normal to the plane of
the detection zone), at any speed between 0 m/s and 1,6 m/s.
The sensing device of a light beam device shall be actuated and the OSSD(s) shall go to the
OFF-state when a test piece in accordance with 4.2.13 is present in the beam centre-line, at
any point throughout the operating distance, with the axis of the cylinder normal to the axis of
the beam.
NOTE The purpose of this requirement is to ensure that the OSSD(s) go to the OFF-state when a person or part
of a person passes through the detection zone or light beam. Based on a dimension of 150 mm and a walking
speed of 1,6 m/s, a minimum OFF time of 80 ms was determined to be adequate.
When the OSSD(s) go to the OFF-state, they shall remain in the OFF-state while the test
piece is present in the detection zone (or light beam) or for at least 80 ms, whichever is
greater.
Where the supplier states that an AOPD can be used to detect objects moving at speeds
greater than those specified above, the above requirements shall be met at any speed up to
and including the stated maximum speed(s).

---------------------- Page: 13 ----------------------

61496-2  IEC:2006 – 19 –
4.1.2.2 Optical performance
The AOPD shall be designed and constructed to:
a) limit the possibility of failure to danger resulting from extraneous reflections (for
example, for operating range up to 3 m, see Figure 1);
b) limit the misalignment at which normal operation is possible;
c) limit the possibility of malfunction during exposure to extraneous light in the range of
400 nm to 1 500 nm;
d) control the size of the emitted beam to minimize the effects on other equipment.
One method of achieving these requirements is by ensuring that the effective aperture angle
(EAA) of each emitting and each receiving element does not exceed the values given in
Figure 2. When this method is used, the requirements are met when the AOPD conforms to
the tests in 5.2.9.2 and Annex D.
There are other technical means alternative to the restriction of the EAA to achieve equivalent
performance for the characteristics in items a), b), c) and d) above. In such cases, the
requirements are met when the AOPD conforms to the tests in 5.2.9.2 and Annex E.
Acceptable optical performance shall be verified by passing the appropriate tests of 5.2.9 and
5.4.
If the AOPD is intended to provide protection when mounted very close to a reflective surface
(i.e. inside the shaded area of Figure 1), the AOPD shall be designed in such a manner that
no optical bypassing can occur on the reflective surfaces. For such a device, an EAA much
less than 2,5 ° (for example, less than 0,1 °) can be necessary. In this case, Figures 1 and 2
do not apply and the limits of protection against optical bypassing shall be as specified by the
manufacturer.

35°
d
d
L
IEC  2491/05
For Type 4: d = 131mm, L = 250 to 3 000 mm
For Type 2: d = 262 mm, L = 500 to 3 000 mm
Figure 1 – Limit area for the protection against the risk of beam bypass

---------------------- Page: 14 ----------------------

61496-2  IEC:2006 – 21 –


MP4* MP3 MP2 MP1
α
MP1
0,5 m
0,75 m
1,5 m
Beam centre-line
3,0 m (or minimum operating distance when >3,0 m)
IEC  2492/05


Type 2 Type 4
MP1 MP2 MP3 MP4 MP1 MP2 MP3 MP4
AOPD AOPD
α Limit α Limit
values values
5 10 19,3 27,7 2,5 5 10 14,7
degrees
degrees
* MP measuring point

NOTE 1 The effective aperture angle should be determined according to 5.2.9.2.
NOTE 2 Measurements should be carried out at each of the measuring points MP1 to MP4 (or if minimum
distance is greater than 3,0 m, at MP1 only).
NOTE 3 The limit values for other distances can be calculated using the formula:
–1
 α = tan (d/L)  where d = 262 (for Type 2)
 or d = 131 (for Type 4)
and L is the distance between emitter and receiver (or DUT and retro-reflector target).
NOTE 4 For retro-reflector systems, the value of α is one-half of the value shown in the table above.
Figure 2 – Measurement of the effective aperture angle (EAA)
4.1.2.3 Additional requirements for an AOPD using retro-reflective techniques
An AOPD using retro-reflect
...