1 Scope
1.1 This part of GB/T 20438 contains an overview of various safety techniques and measures relevant to GB/T 20438.2 and GB/T 20438.3.
The references should be considered as basic references to methods and tools or as examples, and may not represent the state of the art.
1.2 GB/T 20438.1, GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 are basic safety publications, although this status does not apply in the context of low complexity E/E/PE safety-related systems (see 3.4.3 of GB/T 20438.4-2017). As basic safety publications, they are intended for use by technical committees in the preparation of standards in accordance with the principles contained in IEC Guide 104 and ISO/IEC Guide 51. GB/T 20438.1, GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 are also intended for use as stand-alone standards. The horizontal safety function of GB/T 20438 does not apply to medical equipment in compliance with the IEC 60601 series.
1.3 One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. In this context, the requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the publications prepared by those technical committees.
1.4 Figure 1 shows the overall framework of the GB/T 20438 series and indicates the role that this part plays in the achievement of functional safety for E/E/PE safety-related systems.
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Definitions and abbreviations
Annex A (Informative) Overview of techniques and measures for E/E/PE safety-related systems: control of random hardware failures (see GB/T 20438.2)
Annex B (Informative) Overview of techniques and measures for E/E/PE safety-related systems: Avoidance of systematic failures (see GB/T 20438.2 and GB/T 20438.3)
Annex C (Informative) Overview of techniques and measures for achieving software safety integrity (see GB/T 20438.3)
Annex D (Informative) A probabilistic approach to determining software safety integrity for pre-developed software
Annex E (Informative) Overview of techniques and measures for design of ASICs
Annex F (Informative) Definitions of properties of software lifecycle phases
Annex G (Informative) Guidance for the development of safety-related object oriented software
Bibliography
Index
Figure 1 Overall framework of GB/T 20438
Table C.1 Recommendations for specific programming languages
Table D.1 Necessary history for confidence to safety integrity levels
Table D.2 Probabilities of failure for low demand mode of operation
Table D.3 Mean distances of two test points
Table D.4 Probabilities of failure for high demand or continuous mode of operation
Table D.5 Probability of testing all program properties
Table F.1 Software Safety Requirements Specification (see GB/T 20438.3-2017, 7.2 and Table C.1)
Table F.2 Software design and development: software architecture design (see GB/T 20438.3-2017, 7.4.3 and Table C.2)
Table F.3 Software design and development: support tools and programming language (see GB/T 20438.3-2017, 7.4.4 and Table C.3)
Table F.4 Software design and development: detailed design (see GB/T 20438.3-2017, 7.4.5, 7.4.6 and Table C.4)
Table F.5 Software design and development: software module testing and integration (see GB/T 20438.3-2017, 7.4.7, 7.4.8 and Table C.5)
Table F.6 Programmable electronics integration (hardware and software) (see GB/T 20438.3-2017, 7.5 and Table C.6)
Table F.7 Software aspects of system safety validation (see GB/T 20438.3-2017, 7.7 and Table C.7)
Table F.8 Software modification (see GB/T 20438.3-2017, 7.8 and Table C.8)
Table F.9 Software verification (see GB/T 20438.3-2017, 7.9 and Table C.9)
Table F.10 Functional safety assessment (see GB/T 20438.3-2017, Clause 8 and Table C.10)
Table G.1 Object Oriented Software Architecture
Table G.2 Object Oriented Detailed Design
Table G.3 Some Oriented Detailed terms
1 Scope
1.1 This part of GB/T 20438 contains an overview of various safety techniques and measures relevant to GB/T 20438.2 and GB/T 20438.3.
The references should be considered as basic references to methods and tools or as examples, and may not represent the state of the art.
1.2 GB/T 20438.1, GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 are basic safety publications, although this status does not apply in the context of low complexity E/E/PE safety-related systems (see 3.4.3 of GB/T 20438.4-2017). As basic safety publications, they are intended for use by technical committees in the preparation of standards in accordance with the principles contained in IEC Guide 104 and ISO/IEC Guide 51. GB/T 20438.1, GB/T 20438.2, GB/T 20438.3 and GB/T 20438.4 are also intended for use as stand-alone standards. The horizontal safety function of GB/T 20438 does not apply to medical equipment in compliance with the IEC 60601 series.
1.3 One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its publications. In this context, the requirements, test methods or test conditions of this basic safety publication will not apply unless specifically referred to or included in the publications prepared by those technical committees.
1.4 Figure 1 shows the overall framework of the GB/T 20438 series and indicates the role that this part plays in the achievement of functional safety for E/E/PE safety-related systems.
Contents of GB/T 20438.7-2017
Foreword i
Introduction iii
1 Scope
2 Normative references
3 Definitions and abbreviations
Annex A (Informative) Overview of techniques and measures for E/E/PE safety-related systems: control of random hardware failures (see GB/T 20438.2)
Annex B (Informative) Overview of techniques and measures for E/E/PE safety-related systems: Avoidance of systematic failures (see GB/T 20438.2 and GB/T 20438.3)
Annex C (Informative) Overview of techniques and measures for achieving software safety integrity (see GB/T 20438.3)
Annex D (Informative) A probabilistic approach to determining software safety integrity for pre-developed software
Annex E (Informative) Overview of techniques and measures for design of ASICs
Annex F (Informative) Definitions of properties of software lifecycle phases
Annex G (Informative) Guidance for the development of safety-related object oriented software
Bibliography
Index
Figure 1 Overall framework of GB/T 20438
Table C.1 Recommendations for specific programming languages
Table D.1 Necessary history for confidence to safety integrity levels
Table D.2 Probabilities of failure for low demand mode of operation
Table D.3 Mean distances of two test points
Table D.4 Probabilities of failure for high demand or continuous mode of operation
Table D.5 Probability of testing all program properties
Table F.1 Software Safety Requirements Specification (see GB/T 20438.3-2017, 7.2 and Table C.1)
Table F.2 Software design and development: software architecture design (see GB/T 20438.3-2017, 7.4.3 and Table C.2)
Table F.3 Software design and development: support tools and programming language (see GB/T 20438.3-2017, 7.4.4 and Table C.3)
Table F.4 Software design and development: detailed design (see GB/T 20438.3-2017, 7.4.5, 7.4.6 and Table C.4)
Table F.5 Software design and development: software module testing and integration (see GB/T 20438.3-2017, 7.4.7, 7.4.8 and Table C.5)
Table F.6 Programmable electronics integration (hardware and software) (see GB/T 20438.3-2017, 7.5 and Table C.6)
Table F.7 Software aspects of system safety validation (see GB/T 20438.3-2017, 7.7 and Table C.7)
Table F.8 Software modification (see GB/T 20438.3-2017, 7.8 and Table C.8)
Table F.9 Software verification (see GB/T 20438.3-2017, 7.9 and Table C.9)
Table F.10 Functional safety assessment (see GB/T 20438.3-2017, Clause 8 and Table C.10)
Table G.1 Object Oriented Software Architecture
Table G.2 Object Oriented Detailed Design
Table G.3 Some Oriented Detailed terms
