IEC 61496-3:2025

IEC 61496-3 ®
Edition 4.0 2025-08
INTERNATIONAL
STANDARD
COMMENTED VERSION
Safety of machinery - Electro-sensitive protective equipment -
Part 3: Particular requirements for active opto-electronic protective devices
responsive to diffuse reflection (AOPDDR)
ICS 13.110; 31.260 ISBN 978-2-8327-0662-6
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CONTENTS
FOREWORD . 4
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 9
3 Terms, definitions and abbreviated terms . 9
3.1 Terms and definitions. 9
3.1012 Abbreviated terms . 12
4 Functional, design and environmental requirements . 12
4.1 Functional requirements. 12
4.2 Design requirements . 13
4.3 Environmental requirements . 25
5 Testing . 29
5.1 General . 29
5.2 Functional tests . 30
5.3 Performance testing under fault conditions . 41
5.4 Environmental tests . 42
6 Marking for identification and for safe use . 63
6.1 General . 63
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 . 73
Annex AA (informative) Examples of the use of an AOPDDR in different applications . 74
Annex BB (informative) Relationship between position accuracy and probability of
detection for a Type 3 AOPDDR . 97
Bibliography . 104
List of comments. 105

Figure 1 – Detection zone of an AOPDDR-2D . 18
Figure 2 – Detection zone of an AOPDDR-3D . 19
Figure 3 – AOPDDR used as a trip device with orthogonal approach (200 mm minimum
detectable object size) .
Figure 4 – AOPDDR used as a trip device with orthogonal approach (150 mm minimum
detectable object size) .
Figure 3 – Shape of test pieces for AOPDDR-3D . 23
Figure 54 – Minimum diffuse reflectivity of materials . 24
Figure 65 – Test piece intrusion into the detection zone for test . 31
Figure 76 – Influence on detection capability by incandescent light – Example 1 . 36
Figure 87 – Influence on detection capability by incandescent light – Example 2 . 37
Figure 98 – Influence on detection capability by light reflected by the background . 38
Figure 109 – Configuration for the endurance test – Example 1 . 39
Figure 1110 – Configuration for the endurance test – Example 2 . 40
Figure 1211 – Interference between two AOPDDR-3D of identical design (opposite
arrangement) . 53
Figure 1312 – Interference between two AOPDDR-3D of identical design (parallel
arrangement) . 54
Figure 1413 – Example of an emitting element of an AOPDDR . 56
Figure 1514 – Example of a receiver of an AOPDDR . 56
Figure 1615 – Influence on detection capability by background . 58
Figure 1716 – Multi-path reflection test (top view) . 59
Figure 1817 – Multi-path reflection test (side view) . 59
Figure A.1 – Reference boundary monitoring – Distribution of measurement values . 68
Figure A.2 – Use of an AOPDDR with reference boundary monitoring . 69
Figure A.3 – Use of an AOPDDR as parts of a body trip device. 69
Figure A.4 – AOPDDR used as a trip device with orthogonal approach (150 mm
minimum detectable object size) . 70
Figure A.5 – AOPDDR used as a trip device with orthogonal approach (200 mm
minimum detectable object size) . 71
Figure AA.1 – Example of the use of an AOPDDR-2D on machinery .
Figure AA.2 – Example of the use of an AOPDDR-2D on an AGV .
Figure AA.  AA.1 – Minimum Separation distance S – Example 1 . 83
Figure AA.4 – Overall minimum distance S without tolerance zone – Example 1 .
o
Figure AA.5 – Overall minimum distance S including tolerance zone – Example 1 .
o
Figure AA.2 – Separation distance S including tolerance zone – Example 1 . 85
Figure AA.0 AA.3 – Minimum Separation distance S – Example 2 . 86
Figure AA.7 – Overall minimum distance S without tolerance zone – Example 2 .
o
Figure AA.8 – Overall minimum distance S including tolerance zone – Example 2 .
o
Figure AA.4 – Separation distance S including tolerance zone – Example 2 . 88
Figure AA.9 AA.5 – Application example for body detection of an AOPDDR-3D . 90
Figure AA.10 AA.6 – Limited distance . 92
Figure AA.11 AA.7 – Overlap . 93
Figure AA.12 AA.8 – Reference boundary monitoring – Distribution of measurement
values . 94
Figure AA.13 AA.9 – AOPDDR-2D detection zone angled to the direction of approach –
Orthogonal approach . 95
Figure AA.14 AA.10 – AOPDDR-3D detection zone angled to the direction of approach
– Orthogonal approach . 96
Figure BB.1 – Relationship between position accuracy and detection zone . 97
Figure BB.2 – Relationship between position accuracy, detection zone and the
probabilistic part of the tolerance zone – Example 1 . 98
Figure BB.3 – Relationship between position accuracy, detection zone and the
probabilistic part of the tolerance zone – Example 2 . 99
Figure BB.4 – Relationship between position accuracy, detection zone and tolerance
zone – Example 1 . 100
Figure BB.5 – Relationship between position accuracy, detection zone and tolerance
zone – Example 2 . 100
Figure BB.6 – POD of a single measurement (logarithmic) for a MooM-evaluation with
1 ≤ M ≤ 50 . 102
Figure BB.7 – POD of a single measurement for a MooM-evaluation with 1 ≤ M ≤ 50 in
relation to σ in the case of a normal distribution . 103
Table 1 – Minimum tests required for the verification of detection capability
requirements (see also 4.2.12.1) . 32
Table 2 – Overview of light interference tests . 47
Table B.1 – Sensor array for distance measurement . 73

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Safety of machinery - Electro-sensitive protective equipment -
Part 3: Particular requirements for active opto-electronic protective
devices responsive to diffuse reflection (AOPDDR)

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
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shall not be held responsible for identifying any or all such patent rights.
This commented version (CMV) of the official standard IEC 61496-3:2025 edition 4.0
allows the user to identify the changes made to the previous IEC 61496-3:2018
edition 3.0. Furthermore, comments from IEC TC 44 experts are provided to explain the reasons
of the most relevant changes, or to clarify any part of the content.
A vertical bar appears in the margin wherever a change has been made. Additions are in green
text, deletions are in strikethrough red text. Experts' comments are identified by a blue-
background number. Mouse over a number to display a pop-up note with the comment.
This publication contains the CMV and the official standard. The full list of comments is available
at the end of the CMV.
IEC 61496-3 has been prepared by IEC technical committee 44: Safety of machinery –
Electrotechnical aspects. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2018. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) some requirement clauses and test procedures have been adapted or removed because
they have been consolidated in IEC 61496-1:2020 (e.g. 5.4.6.2 Light sources and
Clause A.9);
b) change of the minimum probability of detection and fault detection requirements for Type 2
AOPDDR;
c) using the AOPDDR as a trip device is described as an optional function in Clause A.13.
The text of this International Standard is based on the following documents:
Draft Report on voting
44/1061/FDIS 44/1065/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
This document is to be used in conjunction with IEC 61496-1:2020.
The language used for the development of this International Standard is English.
A list of all parts in the IEC 61496 series, published under the general title Safety of machinery
– Electro-sensitive protective equipment, can be found on the IEC website.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
This document supplements or modifies the corresponding clauses in IEC 61496-1:2020 to
specify 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 responsive to diffuse reflection (AOPDDR) for the sensing function.
Where a particular clause or subclause of IEC 61496-1:2020 is not mentioned in this document,
that clause or subclause applies as far as is reasonable. Where this document states "addition"
or "replacement", the relevant text of IEC 61496-1:2020 is adapted accordingly.
Clauses and subclauses which are additional to those of IEC 61496-1:2020 are numbered
sequentially, following on the last available number in IEC 61496-1:2020. Terminological entries
(in Clause 3) which are additional to those in IEC 61496-1:2020 are numbered starting from
3.301. Additional annexes are lettered from AA onwards.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
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 document supplements or modifies the corresponding clauses in IEC 61496-1:2020 to
specify 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 responsive to diffuse reflection (AOPDDRs) for the sensing
function.
Each type of machine presents its own particular hazards, and it is not the purpose of this
document to recommend the manner of application of the ESPE to any particular machine. The
application of the ESPE is 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, in IEC 62046 and ISO 12100.
The group responsible for drafting this document was concerned that, due to the complexity of
the technology, there are many issues that are highly dependent on analysis and expertise in
specific test and measurement techniques. In order to provide a high level of confidence,
independent review by relevant experts is recommended. If this high level of confidence cannot
be established, these devices would not be suitable for use in safety related applications.

1 Scope
This document specifies additional requirements for the design, construction and testing of
non-contact 1 electro-sensitive protective equipment (ESPE) designed specifically to detect
persons or parts of persons as part of a safety-related system, employing active opto-electronic
protective devices responsive to diffuse reflection (AOPDDRs) for the sensing function. Special
attention is directed to requirements which ensure that an appropriate safety-related
performance is achieved. An ESPE can include optional safety-related functions, the
requirements for which are given both in Annex A of this document and in Annex A of
IEC 61496-1:20122020.
NOTE "Non-contact" means that physical contact is not required for sensing.
This document 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.
AOPDDRs are devices that have either
– one or more detection zone(s) specified in two dimensions (AOPDDR-2D), or
– one or more detection zone(s) specified in three dimensions (AOPDDR-3D)
wherein radiation in the near infrared range is emitted by an emitting element(s). When the
emitted radiation impinges on an object (for example, a person or part of a person), a portion
of the emitted radiation is reflected to a receiving element(s) by diffuse reflection. This reflection
is used to determine the position of the object.
Opto-electronic devices that perform only a single one-dimensional spot-like distance measure-
ment, for example, optical proximity switches, are not covered by this document.
This document is limited to ESPE that do not require human intervention for detection. It is
limited to ESPE that detect objects entering into or being present in a detection zone(s). 2
This document does not address those aspects required for complex classification or
differentiation of the object detected.
This document does not address requirements and tests for outdoor application.
Excluded from this document are AOPDDRs employing radiation with the peak of wavelength
outside the range 820 nm to 950 1 100 nm 3, and those employing radiation other than that
generated by the AOPDDR itself. For sensing devices that employ radiation of wavelengths
outside this range, this document can be used as a guide. This document is relevant for
AOPDDRs having a minimum detectable object size in the range from 30 mm to 200 mm.
This document can be relevant to applications other than those for the protection of persons,
for example, for the protection of machinery or products from mechanical damage. In those
applications, different requirements can be appropriate, for example when the materials that
have to be are recognized by the sensing function have different properties from those of
persons and their clothing.
This document does not deal with electromagnetic compatibility (EMC) emission requirements.
2 Normative references
IEC 61496-1:20122020, Clause 2 is applicable except as follows.
Addition:
IEC 60068-2-14:2023, Environmental testing - Part 2-14: Tests - Test N: Change of temperature
IEC 60068-2-75:2014, Environmental testing - Part 2-75: Tests - Test Eh: Hammer tests
IEC TR 60721-4-5, Classification of environmental conditions – Part 4-5: Guidance for the
correlation and transformation of environmental condition classes of IEC 60721-3 to the
environmental tests of IEC 60068 – Ground vehicle installations
IEC 60825-1:2014, Safety of laser products - Part 1: Equipment classification and requirements
IEC 61496-1:20122020, Safety of machinery - Electro-sensitive protective equipment - Part 1:
General requirements and tests
IEC 62471:2006, Photobiological safety of lamps and lamp systems
IEC TS 62998-1:2019, Safety of machinery - Safety-related sensors used for the protection of
persons
IEC TS 62998-3:2023, Safety of machinery - Safety-related sensors used for the protection of
persons - Part 3: Sensor technologies and algorithms
ISO 13855:20102024, Safety of machinery - Positioning of safeguards with respect to the
approach speeds of parts of the human body
ISO 20471:2013, High visibility clothing - Test methods and requirements
3 Terms and definitions 4
IEC 61496-1:20122020, Clause 3 is applicable except as follows.
Replacement of the title with the following:
3 Terms, definitions and abbreviated terms
Addition:
3.1 Terms and definitions
Definition 3.1 is not applicable.
Replacement:
3.3
detection capability
ability to detect the specified test pieces (see 4.2.13) in the specified
detection zone
Note 1 to entry: A list of influences which can affect the AOPDDR detection capability is given in 4.2.12.1.
Note 2 to entry: Detection capability is often described by the minimum detectable object size and the object
reflectivity. The supplier can state more than one value as the minimum detectable object size, for example depending
on distances or mounting conditions. For an AOPPDR-2D the minimum detectable object size is the diameter of the
cylindrical test piece.
Note 3 to entry: A decrease of detection capability does not mean that a smaller object can be detected.
3.4
detection zone
zone within which the specified test piece(s) (see 4.2.13) is detected by the
AOPDDR with a minimum required probability of detection (see 4.2.12.2)
Note 1 to entry: A tolerance zone is necessary to achieve the required probability of detection of the specified test
piece(s) within the detection zone.
Addition:
3.301
active opto-electronic protective device responsive to diffuse reflection
AOPDDR
device, whose sensing function is performed by opto-electronic emitting and receiving
elements, that detects the diffuse reflection of optical radiations generated within the device by
an object present in a detection zone specified in two or three dimensions
Note 1 to entry: A receiving element can be composed by optics/optic-arrays and a single sensor element(s) or a
sensor array(s).
Note 2 to entry: This note applies to the French language only.
assembly using active optical radiation to detect the diffuse reflection of an object present in a
detection zone specified in two or three dimensions
3.302
AOPDDR-2D
AOPDDR that has one or more detection zone(s) specified in two dimensions
Note 1 to entry: For example, a third dimension is not greater than the minimum detectable object size, then the
AOPDDR is regarded as 2D (see Figures 1 and 2).
Note 2 to entry: A typical example of an AOPDDR-2D is A laser scanner that performs distance measurement by
measuring the time a pulse needs for travelling from the sensing device to an object and back to the sensing device.
An AOPDDR-2D that has more than one detection zone may carry out distance measurements in different planes.
Note 3 to entry: This note applies to the French language only.
EXAMPLE A laser scanner that performs distance measurement by measuring the time a pulse needs for travelling
from the sensing device to an object and back to the sensing device. An AOPDDR-2D that has more than one
detection zone can carry out distance measurements in different planes.
Note 1 to entry: When the third dimension of each detection zone is not greater than the minimum detectable object
size, the AOPDDR is regarded as 2D.
3.303
AOPDDR-3D
AOPDDR that has one or more detection zone(s) specified in three dimensions
Note 1 to entry: For example, a third dimension as specified by the supplier is greater than the minimum detectable
object size, the AOPDDR is regarded as 3D (see Figures 1 and 2). The detection zone(s) can be set-up for example
as a volume in the shape of a pyramid or a cone.
Note 2 to entry: Typical examples of AOPDDR-3D are laser scanners with two perpendicular positioned moving
mirrors or time-of-flight-cameras (TOF) that perform distance measurement on several pixels. An AOPDDR-3D that
has more than one detection zone may carry out distance measurements in different volumes.
Note 3 to entry: This note applies to the French language only.
EXAMPLE A laser scanner with two perpendicular positioned moving mirrors or time-of-flight-cameras (TOF) that
perform distance measurement on several pixels. An AOPDDR-3D that has more than one detection zone can carry
out distance measurements in different volumes.
Note 1 to entry: When the third dimension of each detection zone is greater than the minimum detectable object
size, the AOPDDR is regarded as 3D. The detection zone(s) can be set-up for example as a volume in the shape of
a pyramid or a cone.
3.304
basic test distance
BTD
Radius, respectively width and length (or equivalent values), of the detection zone used for test
set-up
Note 1 to entry: For dimension of BTD, see 5.1.1.2.
Note 2 to entry: This note applies to the French language only.
3.305304
centre axis
line through the origin of distance measurement and the centre of the maximum detection zone
stated by the supplier
Note 1 to entry: See Figure 1 and Figure 2.
3.306305
corner axis
line through the origin of distance measurement and defined by the bounding line of the
detection zone
Note 1 to entry: See Figure 1 and Figure 2.
3.306
maximum detection zone
largest dimension of the detection zone specified by the supplier
3.307
minimum detection zone
lowestsmallest dimension of the detection zone which is necessary to ensure the integrity of
the detection capability
3.308
position accuracy
accuracy in two one or three dimensions more dimension(s) of the position of an object as
measured by the AOPDDR
3.309
tolerance zone
TZ
zone outside of and adjacent to the detection zone within which the specified test piece(s) (see
4.2.13) is detected with a probability of detection lower than the required probability within the
detection zone
Note 1 to entry: The tolerance zone is necessary to achieve the required probability of detection of the specified
test piece(s) within the detection zone
Note 2 to entry: For explanation of the concept of probability of detection and the tolerance zone, see Annex BB.
Note 3 to entry: This note applies to the French language only.
3.310
zone with limited detection capability
zone between the optical window and the beginning of the detection zone, where the detection
capability is not achieved
Note 1 to entry: The dimensions and appropriate information for use of the zone with limited detection capability
are provided by the supplier.
Addition:
3.1012 Abbreviated terms
AGV automated guided vehicle
AOPDDR active opto-electronic protective device responsive to diffuse reflection
BTD basic test distance
ESPE electro-sensitive protective equipment
lx Lux
OSSD output signal switching device
POD probability of detection
SNR signal-to-noise ratio
SRS/SRSS safety-related sensor / safety-related sensor system
TZ tolerance zone
4 Functional, design and environmental requirements
IEC 61496-1:2020, Clause 4 is applicable except as follows.
4.1 Functional requirements
4.1.2 Sensing function 5
Addition:
The detection zone shall begin at the border of the zone with limited detection capability and
end within the maximum operating distance.
Object(s) in the zone with limited detection capability shall not reduce the detection capability
within the detection zone. Any reduction of the detection capability shall be detected and the
AOPDDR shall go to lock-out condition.
The AOPDDR shall respond by giving appropriate output signal(s) when a test piece is present
anywhere within the detection zone whether static or moving with respect to the AOPDDR.
The supplier shall specify the limits of the detection capability. The supplier shall take into
account all influences listed in this document.
4.1.3 Types of ESPE
Replacement:
In this document, only type 2 and type 3 ESPE are considered. The types differ in their
performance in the presence of faults and, under influences from environmental conditions. and
for AOPDDR in the probability of detection. It is the responsibility of the machine supplier and/or
the user to prescribe specify which type is suitable for a particular application.
If IEC TS 62998-1 is applied in addition to this document (see e.g. 4.2.13.2), then the
requirements of SRS/SRSS performance class C for type 2 ESPE and SRS/SRSS performance
class D for type 3 ESPE shall be used. 6
The type 2 ESPE shall fulfil the fault detection requirements of 4.2.2.3 of this document. In
normal operation, the output circuit of each of at least two output signal switching devices
(OSSDs) or of one output signal switching device (OSSD) and one secondary switching device
(SSD) of the type 2 ESPE 7 shall go to the OFF-state when the sensing device is actuated, or
when the power is removed from the device.
The type 3 ESPE shall fulfil the fault detection requirements of 4.2.2.4 of this document. In
normal operation, the output circuit of each of at least two output signal switching devices
(OSSDs) of the type 3 ESPE shall go to the OFF-state when the sensing device is actuated, or
when the power is removed from the device.
When a single safety-related data interface is used to perform the functions of the OSSD(s),
then the data interface and associated safety-related communication interface shall meet the
requirements of 4.2.4.4. In this case, a single safety-related data interface can substitute for
two OSSDs in a type 3 ESPE.
Addition:
4.1.6 Zone(s) with limited detection capability
In order to ensure no hazard can arise in a particular application due to the presence of one or
more zone(s) with limited detection capability between the optical window and the detection
zone, its, the zone's dimensions and appropriate information for use shall be provided by the
supplier.
If the zone with limited detection capability extends more than 50 mm from the optical window
in the direction to the detection zone(s), then additional and effective technical measures shall
be applied to prevent undetected presence of objects or persons or parts of persons in the zone
with limited detection capability.
4.2 Design requirements
4.2.2 Fault detection requirements
4.2.2.2 Particular requirements for a type 1 ESPE
IEC 61496-1:20122020, 4.2.2.2 is not applicable.
4.2.2.3 Particular requirements for a type 2 ESPE
Replacement:
A type 2 ESPE shall have a means of periodic test to reveal a failure to danger (for example
loss of detection capability, response time exceeding that specified).
The test shall be performed also at power-on of the ESPE before going to the ON-state and at
each reset.
Depending on the application, the periodic test may need to be performed more often to achieve
a desired safety performance. Generic functional safety standards give requirements how often
periodic test have to be applied to fulfil the requirements for a certain safety performance.
NOTE 1 The periodic test can be initiated by external or internal means.
When it is not possible to reveal a failure to danger by periodic tests other equivalent measures
shall be applied.
A single fault resulting in the loss of the stated AOPDDR detection capability or the increase in
response time beyond the specified time or preventing one or more of the OSSDs going to the
OFF-state shall result in a lock-out condition as a result of the next periodic test. 8
Addition:
A single fault resulting in the deterioration of the stated AOPDDR detection capability shall
result in a lock-out condition at least as a result of the next periodic test. If the periodic test
cycle is less than 5 s 1 min 9 then deterioration of the stated AOPDDR detection capability
shall be detected within 5 s 1 min.
NOTE 2 Examples of EXAMPLE Deterioration of the AOPDDR detection capability includeincludes:
– the increase of the minimum detectable object size,
– the increase in the minimum detectable reflectivity, and;
– the decrease of position accuracy.
The occurrence of single faults shall be considered by analysis and/or test with each of the
following conditions and throughout the entire detection zone:
– environmental conditions specified in 4.3;
– at the limits of alignment and/or adjustment.
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).
The duration of the periodic test shall be such that the intended safety function is not impaired,
especially if the ESPE is intended for use as a trip device. 10
If the periodic test is automatically initiated, the correct functioning of the periodic test shall be
monitored. In the event of a fault, the OSSD(s) shall be signalled to go to the OFF-state. If one
or more OSSDs do(es) not go to the OFF-state, a lock-out condition shall be initiated.
An ESPE with only one OSSD shall have a minimum of one SSD (see Clause A.4 of IEC 61496-
1:2012). 11
When it is not possible to reveal a failure to danger by periodic tests, other equivalent measures
shall be applied.
4.2.2.4 Particular requirements for a type 3 ESPE
Replacement:
A single fault in the sensing device resulting in a complete loss of the stated AOPDDR detection
capability shall cause the ESPE to go to a lock-out condition within the specified response time. 12
Addition:
NOTE 1 For AOPDDR using rotating mirrors for scanning the detection zone, this requirement can be fulfilled by
scanning on a defined reference object located outside the detection zone and the tolerance zone.
A single fault resulting in a deterioration of the stated AOPDDR detection capability shall cause
the ESPE to go to a lock-out condition within a time period of 5 s following the occurrence of
that fault. 13
NOTE 2 Examples of deterioration of the AOPDDR detection capability include
EXAMPLE Deterioration of the AOPDDR detection capability includes:
– the increase of the minimum detectable object size,
– the increase in the minimum detectable reflectivity, and
– the decrease of position accuracy.
A single fault resulting in an increase in response time beyond the specified value or preventing
at least one OSSD going to the OFF-state shall cause the ESPE to go to a lock-out condition
within the response time, or immediately upon any of the following demand events where fault
detection requires a change in state:
– on actuation of the sensing function;
– on switch off/on;
– on reset of the start interlock or the restart interlock, if available (see Clauses A.5 and A.6
of IEC 61496-1:2012);
– on the application of an external test signal, if available. 14
An external test signal can be required if, for example, in a particular application, the frequency
of actuation of the sensing function is foreseeably low and the OSSDs are monitored at the
change of state only.
In cases where a single fault which in itself does not cause a failure to danger is not detected,
the occurrence of one additional fault shall not cause a failure to danger. For verification of this
requirement, see 5.3.4.
The occurrence of single faults shall be considered by analysis and/or test with each of the
following conditions and throughout the entire detection zone:
– environmental conditions specified in 4.3;
– at the limits of alignment and/or adjustment. 15
4.2.2.5 Particular requirements for a type 4 ESPE
IEC 61496-1:20122020, 4.2.2.5 is not applicable.
Addition:
4.2.12 Integrity of the AOPDDR ESPE detection capability
Replacement:
4.2.12.1 General
The design of the AOPDDR shall ensure that the detection capability is not decreased below
the limits specified by the supplier and in this document by any of, but not limited to, the
following:
a) reflectivity of objects in the range defined for the test pieces to be detected;
b) the position, size and number of objects within the detection zone;
c) the size of detection zones;
d) auto-adjustment, for example the following:
1) gain control;
2) sample rate;
3) shutter time;
4) optical characteristics;
e) properties/ and/or limitations of the emitting/ and/or receiving element, optics and signal
processing, for example the following:
1) signal noise;
2) dynamic range;
3) sensitivity and uniformity (e.g. cold and hot pixels);
4) micro-lenses;
5) change of characteristics;
f) calibration of the sensing device;
g) accuracy of object position in image(s);
h) at the limits of alignment and/or adjustment;
i) environmental conditions specified in 4.3;
j) component tolerances;
k) changing of characteristics of internal and external references to ensure the detection
capability.
NOTE 1 Under certain circumstances, limitations of the sensor in relation to its use need to be considered are of
interest. For exampl
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