IEC 60947-5-3:2013
(Main)Low-voltage switchgear and controlgear - Part 5-3: Control circuit devices and switching elements - Requirements for proximity devices with defined behaviour under fault conditions (PDDB)
Low-voltage switchgear and controlgear - Part 5-3: Control circuit devices and switching elements - Requirements for proximity devices with defined behaviour under fault conditions (PDDB)
IEC 60947-5-3:2013 series provides additional requirements to those given in IEC 60947-5-2. It addresses the fault performance aspects of proximity devices with a defined behaviour under fault conditions (PDDB). It does not address any other characteristics that can be required for specific applications. This second edition replaces the first edition published in 1999 and its amendment published in 2005. It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) general principles of IEC 61508 series;
b) classification according to the requirements of IEC 62061;
c) classification according to ISO 13849-1.
This publication is to be read in conjunction with IEC 60947-1:2007 and IEC 60947-5-2:2007..
Appareillage à basse tension - Partie 5-3: Appareils et éléments de commutation pour circuits de commande - Exigences pour dispositifs de détection de proximité à comportement défini dans des conditions de défaut (PDDB)
La CEI 60947-5-3:2013 fournit des exigences supplémentaires à celles énoncées dans la CEI 60947-5-2. Elle couvre les aspects de défaut des dispositifs de détection de proximité à comportement défini (PDDB) dans les conditions de défaut. Elle ne couvre aucune autre fonctionnalité qui peut être requise pour des applications spécifiques. Cette deuxième édition remplace la première édition publiée en 1999 et son amendement publié en 2005. Il s'agit d'une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) principes généraux de la série CEI 61508;
b) classification selon les exigences de la CEI 62061;
c) classification selon l'ISO 13849-1.
Cette publication doit être lue conjointement avec la CEI 60947-1:2007 et IEC 609947-5-2:2007.
General Information
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Standards Content (Sample)
IEC 60947-5-3 ®
Edition 2.0 2013-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –
Part 5-3: Control circuit devices and switching elements – Requirements for
proximity devices with defined behaviour under fault conditions (PDDB)
Appareillage à basse tension –
Partie 5-3: Appareils et éléments de commutation pour circuits de commande –
Exigences pour dispositifs de détection de proximité à comportement défini
dans des conditions de défaut (PDDB)
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IEC 60947-5-3 ®
Edition 2.0 2013-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage switchgear and controlgear –
Part 5-3: Control circuit devices and switching elements – Requirements for
proximity devices with defined behaviour under fault conditions (PDDB)
Appareillage à basse tension –
Partie 5-3: Appareils et éléments de commutation pour circuits de commande –
Exigences pour dispositifs de détection de proximité à comportement défini
dans des conditions de défaut (PDDB)
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
CODE PRIX U
ICS 29.130.20 ISBN 978-2-8322-1030-7
– 2 – 60947-5-3 © IEC:2013
CONTENTS
FOREWORD . 4
1 General . 6
1.1 Scope . 6
1.2 Normative references . 6
2 Terms, definitions and abbreviations . 8
2.1 General . 8
2.2 Alphabetic index of terms . 8
2.3 Basic terms and definitions . 9
2.4 Terms and definitions concerning the architectural constraints . 12
2.5 Terms and definitions concerning the parts of a PDDB . 13
2.6 Terms and definitions concerning the operation of a PDDB . 14
2.7 Symbols and abbreviations . 15
3 Classification . 15
4 Characteristics . 15
4.1 General . 15
4.2 Constructional characteristics . 15
4.2.1 Proximity device with defined behaviour . 15
4.2.2 Specified target . 15
5 Product information . 16
5.1 Nature of information . 16
5.2 Identification . 16
5.3 Marking . 16
5.3.1 General . 16
5.3.2 Connection identification and marking . 16
5.4 Instructions for installation, operation and maintenance. 16
6 Normal service, mounting and transport conditions . 17
6.1 Normal service conditions . 17
6.2 Conditions during transport and storage . 17
6.3 Mounting . 17
7 Constructional and performance requirements . 17
7.1 Constructional requirements . 17
7.1.1 Materials . 17
7.1.2 Current-carrying parts and their connections . 17
7.1.3 Clearance and creepage distances . 17
7.1.4 Vacant . 17
7.1.5 Vacant . 17
7.1.6 Vacant . 17
7.1.7 Terminals . 17
7.1.8 Provision for protective earthing . 18
7.1.9 IP degree of protection (in accordance with IEC 60529) . 18
7.2 Functional safety management . 18
7.3 Functional requirements specification for SRCFs . 18
7.3.1 General . 18
7.3.2 Safety integrity requirements specification for SRCFs . 18
7.3.3 Electromagnetic compatibility . 18
7.3.4 Design and development of PDDB . 20
60947-5-3 © IEC:2013 – 3 –
7.4 Information for use . 20
7.4.1 Objective . 20
7.4.2 Documentation for installation, use and maintenance . 20
8 Tests . 21
8.1 Kind of tests . 21
8.1.1 General . 21
8.1.2 Type tests . 21
8.1.3 Routine tests . 21
8.1.4 Sampling tests . 21
8.2 Compliance with constructional requirements . 21
8.3 Performances . 21
8.3.1 Test sequences . 21
8.3.2 General test conditions . 21
8.3.3 Performances under no load, normal and abnormal load conditions . 21
8.3.4 Performances under short-circuit current conditions . 22
8.4 Verification of operating distances . 22
8.5 Verification of resistance to vibration and shock . 22
8.6 Verification of electromagnetic compatibility . 22
9 Modification . 23
9.1 Objective . 23
9.2 Modification procedure . 23
Annex A (informative) Example of a simple control system in accordance with
IEC 61511 series . 24
Bibliography . 28
Figure A.1 – Representation of the equipment under control . 24
Figure A.2 – Architecture of the safety related function . 25
Table 1 – EMC requirements for PDDBs . 19
Table A.1 – Collection of reliability and structure data . 25
– 4 – 60947-5-3 © IEC:2013
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 5-3: Control circuit devices and switching elements –
Requirements for proximity devices with defined
behaviour under fault conditions (PDDB)
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
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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 60947-5-3 has been prepared by subcommittee 17B: Low-voltage
switchgear and controlgear, of IEC technical committee 17: Switchgear and controlgear.
This second edition replaces the first edition published in 1999 and its amendment published
in 2005. It is a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) general principles of IEC 61508 series;
b) classification according to the requirements of IEC 62061;
c) classification according to ISO 13849-1.
This standard is to be read in conjunction with IEC 60947-1, Low voltage switchgear and
controlgear – Part 1: General rules and IEC 60947-5-2, Low-voltage switchgear and
60947-5-3 © IEC:2013 – 5 –
controlgear – Part 5-2: Control circuit devices and switching elements – Proximity switches.
The provisions of Part 1 and Part 5-2 are only applicable to this standard where specifically
called for. The numbering of the subclauses of this standard is sometimes not continuous
because it is based on the numbering of the subclauses of IEC 60947-1 or IEC 60947-5-2.
The text of this standard is based on the following documents:
FDIS Report on voting
17B/1821/FDIS 17B/1826/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all parts in the IEC 60947 series, published under the general title Low-voltage
switchgear and controlgear, can be found on the IEC website.
The committee has decided that the contents of this publication will remain unchanged until
the stability 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.
– 6 – 60947-5-3 © IEC:2013
LOW-VOLTAGE SWITCHGEAR AND CONTROLGEAR –
Part 5-3: Control circuit devices and switching elements –
Requirements for proximity devices with defined
behaviour under fault conditions (PDDB)
1 General
1.1 Scope
This part of IEC 60947 series provides additional requirements to those given in IEC 60947-5-
2. It addresses the fault performance aspects of proximity devices with a defined behaviour
under fault conditions (PDDB). It does not address any other characteristics that can be
required for specific applications.
This standard does not cover proximity devices with analogue output.
This Standard does not deal with any specific requirements on acoustic noise as the noise
emission of control circuit devices and switching elements is not considered to be a relevant
hazard.
For a PDDB used in applications where additional characteristics, dealt with in other
standards, are required, the requirements of all relevant standards apply.
The use of this standard alone does not demonstrate suitability for the implementation of any
specific safety related functionality. In particular, this standard does not provide requirements
for the actuation characteristics of a PDDB, or for means to reduce the effects of mutual
interference between devices, e.g. coded targets. Therefore these and any other application-
specific requirements will need to be considered in addition to the requirements of this
standard.
NOTE 1 Due to their behaviour under fault conditions, PDDBs can, for example, be used as interlocking devices
(see ISO 14119).
NOTE 2 The requirements for electro-sensitive protective equipment for the detection of persons are given in the
IEC 61496 series.
1.2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 60068-2-1:2007, Environmental testing – Part 2-1: Tests – Test A: Cold
IEC 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic
(12 + 12 h cycle)
IEC 60529:1989, Degrees of protection provided by enclosures (IP Code)
Amendment 1:1999
IEC 60947-1:2007, Low-voltage switchgear and controlgear – Part 1: General rules
Amendment 1:2010
60947-5-3 © IEC:2013 – 7 –
IEC 60947-5-1:2003, Low-voltage switchgear and controlgear – Part 5-1: Control circuit
devices and switching elements – Electromechanical control circuit devices
Amendment 1:2009
IEC 60947-5-2:2007, Low-voltage switchgear and controlgear – Part 5-2: Control circuit
devices and switching elements – Proximity switches
Amendment 1:2012
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) – Part 4-2: Testing and
measurement techniques – Electrostatic discharge immunity test
IEC 61000-4-3:2006, Electromagnetic compatibility (EMC) – Part 4-3: Testing and
measurement techniques – Radiated, radio-frequency, electromagnetic field immunity test
Amendment 1:2007
Amendment 2:2010
IEC 61000-4-4:2012, Electromagnetic compatibility (EMC) – Part 4-4: Testing and
measurement techniques – Electrical fast transient/burst immunity test
IEC 61000-4-5:2005, Electromagnetic compatibility (EMC) – Part 4-5: Testing and
measurement techniques – Surge immunity test
IEC 61000-4-6:2008, Electromagnetic compatibility (EMC) – Part 4-6: Testing and
measurement techniques – Immunity to conducted disturbances, induced by radio-frequency
fields
IEC 61000-4-8:2009, Electromagnetic compatibility (EMC) – Part 4-8: Testing and
measurement techniques – Power frequency magnetic field immunity test
IEC 61000-4-11:2004, Electromagnetic compatibility (EMC) – Part 4-11: Testing and
measurement techniques – Voltage dips, short interruptions and voltage variations immunity
tests
IEC 61131-2:2007, Programmable controllers – Part 2: Equipment requirements and tests
IEC 61508-1:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 1: General requirements
IEC 61508-2:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 2: Requirements for electrical/electronic/programmable electronic
safety-related systems
IEC 61508-3:2010, Functional safety of electrical/electronic/programmable electronic safety-
related systems – Part 3: Software requirements
IEC 62061:2005, Safety of machinery – Functional safety of safety-related electrical,
electronic and programmable electronic control systems
Amendment 1:2012
ISO 13849-1:2006, Safety of machinery – Safety-related parts of control systems – Part 1:
General principles for design
– 8 – 60947-5-3 © IEC:2013
2 Terms, definitions and abbreviations
2.1 General
For the purposes of this document, the terms and definitions given in IEC 60947-1 and
IEC 60947-5-2, as well as the following terms, definitions and abbreviations apply.
2.2 Alphabetic index of terms
Reference
A
assured operating distance of a PDDB [S ] .2.6.4
ao
assured release distance of a PDDB [S ] .2.6.5
ar
C
complex component .2.3.4
control and monitoring device .2.5.3
D
dangerous failure .2.3.6
defined behaviour (of PDDB) .2.6.1
diagnostic coverage [DC] .2.4.2
diagnostic test interval .2.4.4
E
equipment under control [EUC] .2.4.7
F
failure (of equipment) .2.3.5
fault .2.3.8
failures in time [FIT] . 2.3.18
H
hardware fault tolerance [HFT] .2.4.3
hardware safety integrity .2.3.11
L
lock-out state .2.6.8
low complexity component .2.3.3
M
mean time to dangerous failure [MTTF ] .2.3.17
d
mission time [T ] .2.6.7
M
mode of operation .2.3.14
O
OFF-state .2.6.2
ON-state .2.6.3
output signal switching device [OSSD] .2.5.2
P
Performance Level [PL].2.3.1
proof test .2.4.5
R
risk time .2.6.6
60947-5-3 © IEC:2013 – 9 –
S
safe failure .2.3.7
safe failure fraction [SFF] .2.4.1
safety integrity .2.3.10
Safety Integrity Level [SIL] .2.3.2
Safety-Related Control Function [SRCF] .2.3.9
safety-related system .2.4.6
sensing means .2.5.1
SIL Claim Limit [SILCL] .2.3.16
software safety integrity .2.3.12
systematic safety integrity .2.3.13
T
target failure measure .2.3.15
2.3 Basic terms and definitions
2.3.1
Performance Level
PL
discrete level (from a to e) used to specify the ability of safety-related parts of control systems
to perform a safety function under foreseeable conditions
[SOURCE: ISO 13849-1:2006, 3.1.23, modified – update of the definition]
2.3.2
Safety Integrity Level
SIL
discrete level (one out of a possible three) for specifying the safety integrity requirements of
the safety-related control functions to be allocated to the safety related parts of the control
system, where safety integrity level three has the highest level of safety integrity and safety
integrity level one has the lowest
Note 1 to entry: SIL 4 is not considered in this standard. For requirements applicable to SIL 4, see IEC 61508
series.
[SOURCE: IEC 62061:2005, 3.2.23, modified – update of the note]
2.3.3
low complexity component
component in which:
– the failure modes are well-defined; and
– the behaviour under fault conditions can be completely defined
Note 1 to entry: Behaviour of the low complexity component under fault conditions may be determined by analytical
and/or test methods.
Note 2 to entry: A subsystem or subsystem element comprising one or more limit switches, operating, possibly via
interposing electro-mechanical relays, one or more contactors to de-energise an electric motor is an example of a
low complexity component.
[SOURCE: IEC 62061:2005, 3.2.7]
2.3.4
complex component
component in which:
– the failure modes are not well-defined; or
– the behaviour under fault conditions cannot be completely defined
– 10 – 60947-5-3 © IEC:2013
[SOURCE: IEC 62061:2005, 3.2.8]
2.3.5
failure
the termination of the ability of an item to perform a required function
Note 1 to entry: After failure the system has a fault.
Note 2 to entry: “Failure” is an event, as distinguished from “fault”, which is a state.
Note 3 to entry: The concept of failure as defined does not apply to items consisting of software only.
[SOURCE: IEC 60050-191:1990, 191-04-01]
2.3.6
dangerous failure
failure of a PDDB that has the potential to cause a hazard or non-functional state
[SOURCE: IEC 62061:2005, 3.2.40, modified – deletion of the notes]
2.3.7
safe failure
failure of a PDDB that does not have the potential to cause a hazard
[SOURCE: IEC 62061:2005, 3.2.41 modified – update of the definition]
2.3.8
fault
state of an item characterized by inability to perform a required function, excluding the
inability during preventive maintenance or other planned actions, or due to lack of external
resources
Note 1 to entry: A fault is often the result of the item itself but can exist without prior failure.
Note 2 to entry: In English the term “fault” and its definition are identical to those given in IEC 60050-191:1990,
191-05-01. In the field of machinery, the French term “défaut” and the German term “Fehler” are used rather than
the term “panne” and “Fehlzustand” that appear with this definition.
[SOURCE: IEC 62061:2005, 3.2.30, modified – new definition and new notes]
2.3.9
Safety-Related Control Function
SRCF
control function with a specified integrity level, partly or completely implemented by a PDDB,
that is intended to maintain the safe condition of the equipment under control or prevent an
immediate increase of the risk(s)
Note 1 to entry: ISO 13849-1 uses the term SRF (safety related function), IEC 61508 series uses SF (safety
function), Terms and definitions concerning the integrity.
[SOURCE: IEC 62061:2005, 3.2.16 modified – new definition and new note]
2.3.10
safety integrity
probability of a safety related control system or its PDDB satisfactorily performing the required
safety-related control functions under all stated conditions
[SOURCE: IEC 62061:2005, 3.2.19, modified – update of the definition and deletion of the
notes]
60947-5-3 © IEC:2013 – 11 –
2.3.11
hardware safety integrity
part of the safety integrity of a safety related control system or its PDDB comprising
requirements for both the probability of dangerous random hardware failures and architectural
constraints
[SOURCE: IEC 62061:2005, 3.2.20, modified – update of the definition]
2.3.12
software safety integrity
part of the safety integrity of a PDDB relating to systematic failures in a dangerous mode of
failure that are attributable to software
Note 1 to entry: Software safety integrity cannot usually be quantified precisely.
[SOURCE: IEC 61508-4:2010, 3.5.5, modified – update of the definition and addition of a
note]
2.3.13
systematic safety integrity
part of the safety integrity of a PDDB relating to systematic failures in a dangerous mode of
failure
Note 1 to entry: Systematic safety integrity cannot usually be quantified (as distinct from hardware safety integrity
which usually can).
Note 2 to entry: Requirements for systematic safety integrity apply to both hardware and software aspects of a
PDDB.
[SOURCE: IEC 61508-4:2010, 3.5.6 modified – update of the definition and addition of a note]
2.3.14
mode of operation
way in which a safety function operates, which may be either:
– low demand mode: where the safety function is only performed on demand, in order to
transfer the EUC into a specified safe state, and where the frequency of demands is no
greater than one per year; or
Note 1 to entry: The E/E/PE safety-related system that performs the safety function normally has no influence on
the EUC or EUC control system until a demand arises. However, if the E/E/PE safety-related system fails in such a
way that it is unable to carry out the safety function then it may cause the EUC to move to a safe state.
– high demand mode: where the safety function is only performed on demand, in order to
transfer the EUC into a specified safe state, and where the frequency of demands is
greater than one per year; or
– continuous mode: where the safety function retains the EUC in a safe state as part of
normal operation
[SOURCE: IEC 61508-4:2010, 3.5.16, modified – update of the note]
2.3.15
target failure measure
intended probability of dangerous mode failures to be achieved in respect of the safety
integrity requirements, specified in terms of either:
– the average probability of dangerous failure to perform the design function on demand
PFD (for a low demand mode of operation);
avg
– the average frequency of a dangerous failure over a given period of time PFH (for a high
D
demand or continuous mode of operation)
– 12 – 60947-5-3 © IEC:2013
Note 1 to entry: The term “probability of dangerous failure per hour” is not used in the standard but the abbreviation
PFH has been retained but when it is used it means “average frequency of dangerous failure”.
Note 2 to entry: The numerical values for the target failure measures are given in Table 2 and Table 3 of
IEC 61508-1:2010. These limit values are valid for the whole safety related function.
[Adapted from IEC 61508-4:2010, 3.5.17]
2.3.16
SIL Claim Limit
SILCL
maximum SIL that can be claimed for a PDDB in relation to architectural constraints and
systematic safety integrity
[SOURCE: IEC 62061:2005, 3.2.24 modified – update of the definition]
2.3.17
mean time to dangerous failure
MTTF
d
expectation of the mean time to dangerous failure
Note 1 to entry: Adapted from IEC 62061:2005, definition 3.2.34.
[SOURCE: ISO 13849-1:2006, 3.1.25]
2.3.18
failure in time
FIT
the number of failures in 10 device-hours of operation
2.4 Terms and definitions concerning the architectural constraints
2.4.1
safe failure fraction
SFF
ratio of the average failure rates of safe failures plus dangerous detected failures of the PDDB
to the total average failure rate (sum of safe failure rate and all dangerous failure rate) of the
PDDB
[Adapted from IEC 61508-4:2010, 3.6.15]
2.4.2
diagnostic coverage
DC
measure of the effectiveness of diagnostics, which may be determined as the ratio between
the failure rate of detected dangerous failures and the failure rate of total dangerous failures
[SOURCE: ISO 13849-1:2006, 3.1.26, modified – deletion of the notes]
fraction of dangerous failures detected by automatic on-line diagnostic tests
Note 1 to entry: The fraction of detected dangerous failures is computed to be the rate of dangerous failures that
are detected by automatic on-line diagnostic tests divided by the rate of total dangerous failures.
Note 2 to entry: There is a different approach between the IEC 62061/IEC 61508 and ISO 13849-1 failure concepts.
Prescriptions for architectural constraints on subsystems according to IEC 62061:2005 (Table 5) are given as a
function of the hardware fault tolerance and the safe failure fraction. ISO 13849-1 does not consider any safe
failure/safe failure fraction. Performance levels are based on well-defined architectures. The achieved PL is then a
function of the architecture, the MTTF , the diagnostic coverage and the common cause failures.
d
[SOURCE: IEC 62061:2005, 3.2.38, modified – update of the notes]
60947-5-3 © IEC:2013 – 13 –
2.4.3
hardware fault tolerance
HFT
ability of a system to perform its safety function in the presence of faults
Note 1 to entry: Hardware fault tolerance of N means that N+1 faults could cause a loss of the safety function. In
determining the hardware fault tolerance no consideration is given to other faults, for example in diagnostics.
[Adapted from IEC 61508-2:2010, 7.4.4.1.1]
2.4.4
diagnostic test interval
interval between on-line tests to detect faults in a safety-related system that has a specified
diagnostic coverage
[SOURCE: IEC 61508-4:2010, 3.8.7]
2.4.5
proof test
periodic test performed to detect failures in a safety-related system so that, if necessary, the
system can be restored to an “as new” condition or as close as practical to this condition
[SOURCE: IEC 61508-4:2010, 3.8.5, modified – update of the definition and deletion of the
notes]
2.4.6
safety-related system
designated system that both
– implements the required safety functions necessary to achieve or maintain a safe state for
the Equipment Under Control; and
– is intended to achieve, on its own or with other E/E/PE safety-related systems, other
technology safety-related systems or external risk reduction facilities, the necessary safety
integrity for the required safety functions
[SOURCE: IEC 61508-4:2010, 3.4.1, modified – deletion of the notes]
2.4.7
equipment under control
EUC
equipment, machinery, apparatus or plant used for manufacturing, process, transportation,
medical or other activities
Note 1 to entry: The EUC control system is separate and distinct from the EUC.
[SOURCE: IEC 61508-4:2010, 3.2.1]
2.5 Terms and definitions concerning the parts of a PDDB
2.5.1
sensing means
part of the PDDB which detects the presence or absence of a defined target
2.5.2
output signal switching device
OSSD
component of the PDDB which goes to the OFF-state according to the defined behaviour
– 14 – 60947-5-3 © IEC:2013
2.5.3
control and monitoring device
device which receives and processes signals from the sensing means, provides signals to the
OSSD(s) and monitors correct operation
2.6 Terms and definitions concerning the operation of a PDDB
2.6.1
defined behaviour
changing of the OSSD(s) to the off-state in the defined position of the specified target and in
accordance with the requirements of this standard
2.6.2
OFF-state
state in which the output circuits interrupts the flow of current other than residual current (I )
r
2.6.3
ON-state
state in which the output circuits permits the flow of current
2.6.4
assured operating distance of a PDDB
S
ao
distance from the sensing face within which the presence of the specified target is correctly
detected under all specified environmental conditions and manufacturing tolerances
2.6.5
assured release distance of a PDDB
S
ar
distance from the sensing face beyond which the absence of the specified target is correctly
detected under all specified environmental conditions and manufacturing tolerances
2.6.6
risk time
maximum period of time during which OSSD(s) can deviate from the defined behaviour
2.6.7
mission time
T
M
period of time covering the intended use of a PDDB
2.6.8
lock-out state
state in which at least one OSSD is OFF and remains in OFF-state until the fault is corrected.
The device enters the lock-out state whenever a fault is detected
60947-5-3 © IEC:2013 – 15 –
2.7 Symbols and abbreviations
Symbol or Description Definition
abbreviation
DC diagnostic coverage 2.4.2
EUC equipment under control 2.4.7
FIT failures in time 2.3.18
HFT hardware fault tolerance 2.4.3
MTTF mean time to dangerous failure 2.3.17
d
OSSD output signal switching device 2.5.2
PFH average frequency of a dangerous failure over a given period of time 2.3.15
D
PFD probability of dangerous failure on demand 2.3.15
PL performance level 2.3.1
S assured operating distance of a PDDB 2.6.4
ao
S assured release distance of a PDDB 2.6.5
ar
SRF safety related function 2.3.9
SFF safe failure fraction 2.4.1
SIL safety integrity level 2.3.2
SILCL SIL claim limit 2.3.16
SRCF safety-related control function 2.3.9
T mission time 2.6.7
M
3 Classification
Clause 3 of IEC 60947-5-2:2007 applies.
4 Characteristics
4.1 General
Clause 4 of IEC 60947-5-2:2007 applies, with the following additions.
4.2 Constructional characteristics
4.2.1 Proximity device with defined behaviour
A PDDB is composed of the following elements:
a) sensing means;
b) OSSD(s);
c) control and monitoring device (when required).
These elements may be integrated into a single device or may be separate devices.
4.2.2 Specified target
The manufacturer shall specify the necessary target to achieve the distances S and S .
ao ar
– 16 – 60947-5-3 © IEC:2013
5 Product informatio
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