Functional Safety of Electrical/Electronic/Programmable Electronic Safety-Related Systems - Part 4: Definitions and Abbreviations
|Publication Date:||1 April 1999|
|ICS Code (Industrial process measurement and control):||25.040.40|
|ICS Code (Electrical engineering in general):||29.020|
This part of IEC 61508 contains the definitions and explanation of terms that are used in parts 1 to 7 of this standard.
The definitions are grouped under general headings so that related terms can be understood within the context of each other. But it should be noted that these headings are not intended to add meaning to the definitions, and in this sense the headings should be disregarded.
IEC 61508-1, IEC 61508-2, IEC 61508-3 and IEC 61508-4 are basic safety publications, although this status does not apply in the context of low-complexity E/E/PE safety-related systems (see 3.4.4). 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. One of the responsibilities of a technical committee is, wherever applicable, to make use of basic safety publications in the preparation of its own publications. IEC 61508 is also intended for use as a stand-alone standard.
Figure 1 shows the overall framework for parts 1 to 7 of IEC 61508 and indicates the role that IEC 61508-4 plays in the achievement of functional safety for E/E/PE safety-related systems.
NOTE - In the USA and Canada, until the proposed process sector implementation of IEC 61508 (i.e. IEC 61511) is published as an international standard in the USA and Canada, existing national process safety standards based on IEC 61508 (i.e. ANSI/ISA S84.01-1996) can be applied to the process sector instead of IEC 61508.