Electromagnetic compatibility―General―Methodology for the achievement of functional safety of electrical and electronic systems including equipment with regard to electromagnetic phenomena
GB/Z 17624.2-2013 Electromagnetic compatibility―General―Methodology for the achievement of functional safety of electrical and electronic systems including equipment with regard to electromagnetic phenomena
1 Scope
This part establishes a methodology for the achievement of functional safety only with regard to electromagnetic phenomena of electrical and electronic systems and installations, as installed and used under operational conditions. This methodology includes the implication it has on equipment used in such systems and installations.
This technical specification:
a) applies to safety-related systems incorporating electrical/electronic/programmable electronic equipment;
b) considers the influence of the electromagnetic environment on safety-related systems; it is intended for designers, manufacturers and installers of safety-related systems and can be used as a guide by IEC committees;
c) is not concerned with direct hazards from electromagnetic fields on living beings nor is it concerned with safety related to breakdown of insulation or other mechanisms by which persons can be exposed to electrical hazards.
It mainly covers EMC related aspects of the design phase of safety-related systems and equipment used therein, and deals in particular with
——some basic concepts in the area of functional safety,
——the various EMC specific steps for the achievement and management of functional safety,
——the description and assessment of the electromagnetic environment,
——the EMC aspects of the design and integration process taking into account the process of EMC safety planning on system as well as on equipment level,
——the validation and verification processes regarding the immunity against electromagnetic disturbances,
——the performance criterion and some test philosophy considerations for safety-related systems and the equipment used therein,
——aspects related to testing of the immunity of safety-related systems and equipment used therein against electromagnetic disturbances.
This Technical Specification is applicable to safety-related systems intended to comply with the requirements of IEC 61508 and/or associated sector-specific functional safety standards.
For safety-related systems covered by other functional safety standards, a consideration shall be made of the requirements of this Technical Specification in order to identify the appropriate measures that shall be taken with relation to EMC and functional safety.
This Technical Specification may also be used as a guide for considering EMC requirements for other systems having a direct contribution to safety.
2 Normative references
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.
IEC Guide 104:1997 The preparation of safety publications and the use of basic safety publications and group safety publications
IEC 60050(161) International Electrotechnical Vocabulary (IEV) - Chapter 161: Electromagnetic compatibility
IEC 61000-2-5 Electromagnetic compatibility (EMC) - Part 2: Environment - Section 5: Classification of electromagnetic environments
IEC 61000-2-13 Electromagnetic compatibility (EMC) - Part 2-13: Environment - Highpower electromagnetic (HPEM) environments - Radiated and conducted
IEC 61000-4 (all parts) Electromagnetic compatibility (EMC) - Part 4: Testing and measurement techniques
IEC 61000-4-1 Electromagnetic compatibility (EMC) - Part 4-1: Testing and measurement techniques - Overview of IEC 61000-4 series
IEC 61508 (all parts) Functional safety of electrical/electronic/programmable electronic safety-related systems
IEC 61508-1 Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 1: General requirements
IEC 61508-2 Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 2: Requirements for electrical/electronic/programmable electronic safety-related systems
IEC 61508-4 Functional safety of electrical/electronic/programmable electronic safety-related systems - Part 4: Definitions and abbreviations
3 Terms, definitions and abbreviations
For the purposes of this document, the definitions contained in IEC 60050 (161) as well as the following apply.
3.1
degradation (of performance)
undesired departure in the operational performance of any device, equipment or system from its intended performance
Note: The term "degradation" can apply to temporary or permanent failure.
[IEV 161-01-19]
3.2
electrical/electronic/programmable electronic; E/E/PE
based on electrical and/or electronic and/or programmable electronic technology
Note: The term is intended to cover any and all devices or systems operating on electrical principles.
Example: Electrical/electronic/programmable electronic devices include
——electro-mechanical devices (electrical);
——solid-state non-programmable electronic devices (electronic);
——electronic devices based on computer technology (programmable electronic).
[IEC 61 508-4]
3.3
electromagnetic compatibility; EMC
ability of an equipment or system to function satisfactorily in its electromagnetic environment without introducing intolerable electromagnetic disturbances to anything in that environment
[IEV 161-01-07]
3.4
electromagnetic compatibility level
specified electromagnetic disturbance level used as a reference level for co-ordination in the setting of emission and immunity limits
Note 1: By convention, the compatibility level is chosen so that there is only a small probability that it will be exceeded by the actual disturbance level. However, electromagnetic compatibility is achieved only if the emission and immunity levels are controlled such that, at each location, the disturbance level resulting from the cumulative emissions is lower than the immunity level for each device, equipment and system situated at the same location.
Note 2: The compatibility level may be phenomena-, time- or location-dependent.
[IEV 161-03-10]
3.5
electromagnetic disturbance
any electromagnetic phenomenon which may degrade the performance of a device, equipment or system, or adversely affect living or inert matter
Note: An electromagnetic disturbance may be an electromagnetic noise, an unwanted signal or a change in the propagation medium itself.
[IEV 161-01-05]
3.6
electromagnetic environment
totality of electromagnetic phenomena existing at a given location
[IEV 161-01-01 ]
3.7
electromagnetic interference; EMI
degradation of the performance of an equipment, transmission channel or system caused by an electromagnetic disturbance
Note: Disturbance and interference are respectively cause and effect.
[IEV 161-01-06]
3.8
equipment
part of system
Note: Equipment as used in this specification is a very general term that refers to a wide variety of possible subsystems, modules, devices and other assemblies of products. It does not include people.
3.9
equipment under control; EUC
equipment, machinery or plant used for manufacturing, process, transportation, medical or other activities
3.10
equipment requirements specification; ERS
equipment specification covering safety-related requirements only with regard to electromagnetic phenomena
Note: An equipment requirements specification (ERS) is created for each item of equipment within the safety-related system. Included in each equipment requirements specification is an electromagnetic performance specification based upon the maximum electromagnetic environment expected over the lifetime for that particular item of equipment.
3.11
failure
termination of the ability of an item to perform a required function
Note 1: The definition in IEV 191-04-01 is the same, with additional notes.
Note 2: For further information, see IEC 61508-4.
Note 3: Performance of required functions necessarily excludes certain behaviour, and some functions may be specified in terms of behaviour to be avoided. The occurrence of such behaviour is a failure.
Note 4: Failures are either random (in hardware) or systematic (in hardware of software).
[ISO/IEC 2382-14-04-11, modified] [IEC 61508-4]
4 General considerations
Electromagnetic disturbances can influence the performance of equipment and the functional safety of systems.
The aim of this document with regard to EMC and functional safety is to address the possible effects of electromagnetic disturbances on safety-related systems and to specify requirements for the relevant phases of the lifecycle of a safety-related system to achieve the systematic capability due to electromagnetic aspects as specified in the safety requirements specification (SRS).
The correct operation of a safety-related system depends on several factors. IEC 61508 contains the overall consideration for safety-related systems. The specific aspects related to electromagnetic disturbances are considered in this technical specification.
These aspects comprise:
——the electromagnetic environment (see Clause 6);
——assessing environment information,
——deriving test levels and methods,
——considerations on electromagnetic phenomena and safety integrity levels (SILs);
——the EMC aspects of the design and integration processes (see Clause 7);
——system level,
——equipment level;
——electromagnetic immunity verification/validation for functional safety (see Clause 8);
——verification and validation processes,
——performance criteria and test philosophy;
——immunity testing with regard to functional safety (see Clause 9);
——considerations on test methods and levels,
——considerations on immunity testing with regard to systematic capability.
Figure 2 shows the mutual relationship between these aspects as well as to those treated within IEC 61508. Though the safety requirements specification (SRS) is primarily an aspect of IEC 61508 it shall consider the outcome of an assessment of the electromagnetic environment in which the safety-related system is intended to be operated.
