CLC/TS 61496-2:2006

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
©  Standard je založil in izdal Slovenski inštitut za standardizacijo. Razmnoževanje ali kopiranje celote ali delov tega dokumenta ni dovoljeno

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

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.
__________
- 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.

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.
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Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch
CODE PRIX
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PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
Pour prix, voir catalogue en vigueur
For price, see current catalogue

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

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

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.

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.
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.

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.
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

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).

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

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-reflective techniques where the light beam traverses the detection zone
more than once (over the same path) shall not fail to danger if a reflective object (for example,
reflective clothes) is placed at any position in the detection zone and shall not be bypassed by
an easily available reflector (for example, mirror).
NOTE The use of mirrors to return the light beam is not considered to be a retro-reflective technique.

61496-2  IEC:2006 – 23 –
The OSSD(s) of a single light beam device shall go to, and remain in, the OFF-state when a
reflective object of a size greater than, or equal to, the diameter and length of the test piece
(see 4.2.13) is placed in the beam at any position as specified in 5.2.1.1.
The reflective objects considered shall consist of:
– the retro-reflector target;
– a retro-reflecting material conforming to the requirements for retro-reflection of
EN 471:2003 class 2 or equivalent;
NOTE Table 5 in EN 471:2003 defines the minimum coefficient of retro-reflection for class 2 material as
1 -2
330 cd lx m with an entrance angle of 5° and an observation angle of 0,2° (12').
– a mirror-type reflective surface having a reflection factor greater than, or equal to, 90 % at
the operating wavelength, for example polished chrome plating or polished aluminium;
– a diffuse reflective surface, for example, white paper.
Under normal operating conditions the OSSD(s) of a light curtain and of a multiple light beam
device using retro-reflective techniques shall go to and remain in the OFF-state when an
identical reflector is placed as close as practicable in front of the sensing surface of the
emitting/receiving element(s).
4.1.2.4 Additional requirements for an AOPD using emitters and receivers in the same
assembly
Under normal operating conditions the OSSD(s) of an AOPD shall go to, and remain in, OFF-
state when a reflective object whose size is greater than, or equal to, the diameter and length
of the test piece is placed normal to the optical axes anywhere within the detection zone.
NOTE This subclause does not apply to an AOPD using retro-reflective techniques.
The reflective objects considered shall consist of
– a retro-reflecting material conforming to the requirements for retro-reflection of EN 471:
2003 class 2 or equivalent;
NOTE Table 5 in EN 471:2003 defines the minimum coefficient of retro-reflection for class 2 material as
1 -2
330 cd lx m with an entrance angle of 5° and an observation angle of 0,2° (12').
– a mirror-type reflective surface having a reflection factor greater than or equal to 90 % at
the operating wavelength, for example, polished chrome plating or polished aluminium;
– a diffuse reflective surface, for example, white paper.
4.2 Design requirements
4.2.2 Fault detection requirements
4.2.2.3 Particular requirements for a type 2 ESPE
Replacement of first paragraph:
A type 2 ESPE shall have a means of periodic test to reveal a failure to danger (for example,
loss of sensing unit detection capability, response time exceeding that specified). The test
shall verify that each light beam operates in the manner specified by the supplier. Where the
periodic test is intended to be initiated by an external (for example, machine) safety-related
control system, the ESPE shall be provided with suitable input facilities (for example,
terminals).
61496-2  IEC:2006 – 25 –
Additional design requirements:
4.2.12 Integrity of the AOPD detection capability
The design of the AOPD shall be such that the AOPD detection capability remains less than,
or equal to, the value stated by the supplier when the AOPD is operated under any and all
combinations of the following:
– any condition within the specification of the supplier;
– the environmental conditions specified in 4.3 (of IEC 61496-1:2004 and IEC 61496-2:
2005);
– at the limits of alignment and/or adjustment.
If a single fault (as specified in Annex B of IEC 61496-1:2004), which under normal operating
conditions (see 5.1.2.1 of IEC 61496-1:2004) would not result in a loss of AOPD detection
capability but, when occurring with a combination of the conditions specified above, would
result in such a loss, that fault together with that combination of conditions shall be
considered as a single fault, and the AOPD shall respond to such a single fault as required in
4.2.2. An example of a method for determining detection capability is shown in Annex E.
4.2.13 Test piece
The test piece shall be cylindrical and opaque, with a minimum effective length of 150 mm.
The diameter of the test piece shall not exceed the AOPD detection capability stated by the
supplier.
For an AOPD detection capability of not more than 40 mm, the test piece for a light curtain
shall be provided by the supplier and shall be marked with the following:
– diameter in millimetres;
– type reference and an indication of the AOPD with which the test piece is intended to be
used.
When more than one detection capability can be configured on the AOPD, the supplier shall
provide a test piece for each detection capability.
Verification shall be by inspection.
4.2.14 Wavelength
AOPDs shall operate at a wavelength within the range 400 nm to 1 500 nm.
4.2.15 Radiation intensity
The radiation intensity generated and emitted by the AOPD shall at no time exceed the
maximum power or energy levels for a class 1M device in accordance with 8.2 of IEC 60825-
1.
NOTE The use of class 2M devices is under consideration.

61496-2  IEC:2006 – 27 –
4.3 Environmental requirements
Addition:
4.3.5 Light interference
The ESPE shall continue in normal operation when subjected to
– incandescent light;
– flashing beacons;
– fluorescent light operated with high-frequency electronic power supply.
The ESPE shall not fail to danger when subjected to
– incandescent light (simulated daylight using a quartz lamp);
– stroboscopic light;
– fluorescent light operated with high-frequency electronic power supply;
– for a type 4 ESPE, radiation from an emitting element of identical design.
NOTE Requirements for protection of type 2 ESPEs from radiation from an emitting element of identical design are
under consideration.
These requirements shall be met when the ESPE conforms to the tests in 5.4.6.
No requirements are given for immunity to other extraneous light sources which may cause
abnormal operation or failure to danger. A requirement for the supplier to inform the user of
potential problems is given in (ff) of Clause 7 (of IEC 61496-1:2004 and IEC 61496-2:2005).
5 Testing
This clause of Part 1 is applicable except as follows:
5.1 General
Addition:
In the following tests, it shall be verified that when the OSSD(s) go to the OFF-state, they
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. If the AOPD incorporates a restart interlock, the
restart interlock shall be disabled during the tests of this clause.
5.1.1 Type tests
5.1.1.2 Operating condition
Addition:
For the purpose of these tests, the plane of the light curtain detection zone may be either
vertical or horizontal as preferred for a test.
If it can be demonstrated that the results will be the same, testing at long operating distances
may be simulated by the use of neutral density filters.

61496-2  IEC:2006 – 29 –
5.1.2 Test conditions
5.1.2.2 Measurement accuracy
Addition to first paragraph:
– for angular measurement: ±0,1°;
– for light intensity measurement: ±10 %.
5.2 Functional tests
Replacement:
5.2.1 Sensing function and detection capability
5.2.1.1 Sensing function
It shall be verified that the sensing device is continuously actuated and, where appropriate,
that the OSSD(s) go to the OFF-state as described in this subclause, taking into account the
operating principle of the AOPD and, in particular, the techniques used to provide tolerance to
environmental interference.
For a light curtain:
– by slowly moving the test piece in the detection zone across the beams at an angle of 45°
and at an angle of 90° (see Figures 3 and 4) at each end of the detection zone [as near as
practical to the emitter and receiver (or retro-reflector)] and midway between the ends (see
Figure 5);
– by placing the test piece in the detection zone, stationary, at any position and/or angle
considered critical as a result of the analysis in 5.2.9.1;
– by moving the test piece in the detection zone, across the beams at the maximum speed in
the range specified in 4.1.2.1, and at any other speed in that range which is considered
critical as a result of the analysis in 5.2.9.1;
– by moving the test piece (having a length of 150 mm) through the detection zone at
1,6 m/s such that the direction of movement and the axis of the test piece are normal to
the detection plane, at the extremities of the detection zone (for example, at each corner)
and in any other position that is considered critical as a result of the analysis in 5.2.9.1.
For a light beam device:
– by placing the test piece in the beam at each end of the beam and midway along the beam
such that the axis of the test piece is normal to the axis of the beam;
– by moving the test piece (having a length of 150 mm) through the beam at 1,6 m/s such
that the direction of movement and the axis of the test piece are normal to the axis of the
beam, at each end of the beam midway along the beam, and at any point throughout the
operating distance which is considered critical as a result of the analysis in 5.2.9.1.
The above tests shall be performed with the AOPD operating at the minimum specified
operating distance or 0,5 m, whichever is the greater, and at the maximum specified operating
distance.
61496-2  IEC:2006 – 31 –
Detection zone of a light curtain
shown with light beams normal
to the page
Test piece
45°
IEC  2493/05
Figure 3 – Test piece at 45°
Detection zone of a light curtain
shown with light beams normal
to the page
Test piece
IEC  2494/05
Figure 4 – Test piece at 90°
61496-2  IEC:2006 – 33 –
TP
TP
TP
IEC  2495/05
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
5.2.1.2 Integrity of the AOPD detection capability
It shall be verified that the AOPD detection capability is continuously maintained or the ESPE
does not fail to danger, by systematic analysis of the design of the AOPD, using testing where
appropriate, taking into account all combinations of the conditions specified in 4.1.2 and
4.2.12, and the faults specified in 5.3.
In cases where it is established that the AOPD detection capability is achieved by optical
geometry based on the complete obscuration of at least one light beam anywhere within the
detection zone (as shown in Annex F), further analysis and testing may not be necessary. In
cases where detection capability is not achieved by complete obscuration, at least the
following additional tests shall be carried out:
a) align the AOPD in accordance with the suppliers specifications;
b) place a neutral density filter with a transmitance of 30 % and with a dimension twice the
size of the detection capability into the detection zone;
c) switch AOPD on and wait for 30 s (or longer, if necessary, on the basis of the analysis of
5.2.9.1). Verify that the OSSD(s) are in the ON-state. If the OSSD(s) are in the OFF-state,
the operating distance shall be reduced and the test restarted;
d) insert the test piece in front of the filter. Verify that the OSSD(s) go to the OFF-state within
the response time;
e) remove the filter and verify that the OSSD(s) continuously remain in the OFF-state;
f) repeat the test at several locations as determined by the analysis of 5.2.9.1.
The results of the systematic analysis shall identify which tests in 5.4 require, in addition, a
measurement of the response time.

61496-2  IEC:2006 – 35 –
5.2.1.3 Additional tests for an AOPD using retro-reflective techniques
The following tests shall be conducted at both the minimum and maximum operating distance
specified by the manufacture.
For a single light beam device, it shall be verified that the sensing device is actuated when a
reflective object (as specified in 4.1.2.3) of a size greater than, or equal to, the diameter and
length of the test piece is placed on, and normal to, the optical axis of the light beam device.
This test shall be conducted near the emitter/receiver, 200 mm in front of the retro-reflector
target and midway along the beam.
For a light curtain and a multiple light beam device using retro-reflective techniques, it shall
be verified that the OSSD(s) go to the OFF-state when a reflector identical to the retro-
reflector target is placed in contact with the sensing surface of the emitting/receiving
element(s).
For a light curtain it shall be verified that the sensing device is actuated when:
a) highly reflective cylindrical object of a size greater than or equal to that of the test piece is
placed within the detection zone of a light curtain, and
b) a reflective object (as specified in 4.1.2.3) is inserted within the detection zone of the light
curtain.
These tests shall be conducted near the emitter/receiver, near the retro-reflector target and
midway along the beam
5.2.1.4 Additional tests for AOPDs using mixed emitter/receivers in the same
assembly
It shall be verified that the sensing device is actuated when a reflective object (as specified in
4.1.2.4) is inserted within the detection zone of the AOPD. The reflective object shall be
placed near the emitter/receiver and midway within the detection zone.
Additional functional tests:
5.2.9 Verification of optical performance
5.2.9.1 Analysis of the electro-optical subsystem
5.2.9.1.1 Analysis
A systematic analysis of the electro-optical subsystem shall be carried out to determine:
a) the beam centre-line and the optical axes of the emitting and receiving elements;
b) the relative intensity/sensitivity off-axis in all directions of the emitting and receiving
elements;
c) confirmation of any filtering techniques employed and their characteristics;
d) the criteria used to determine the status of the sensing function;
e) the relative intensity/sensitivity of the beams in the multibeam devices;
f) the effect of undetected faults, in accordance with 4.2.2, on the electro-optical
characteristics;
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