IEC 61508 series discusses functional safety of electrical/electronic/programmable electronic safety-related systems. IEC 61508 provides a means for users and regulators to gain confidence when using computer-based technology.
PD IEC/TS 61508-3-1 focuses on software requirements which deal with the reuse of software elements when they are intended to form part of a safety function.
PD IEC/TS 61508-3-1 presents requirements by the application of which pre-existing software elements may be claimed to be proven-in-use for all or a part of safety function(s) of SIL1 or SIL2.
A reused software function in PD IEC/TS 61508-3-1 means a function specified on the level of the requirements specification (IEC 61508-3). A reused software function does not refer to a programming language construct.
PD IEC/TS 61508-3-1 on software reuse is useful for:
In many fields of automation, software elements are used today in support of safety functions. Such applications will be further developed and extended. Software engineers do not always wish to write the software for these applications from scratch but will in many cases use already existing software and integrate it with the new application which might be slightly different from the one for which the software was originally specified.
IEC 61508 series aims to release the potential of electrical/electronic/ programmable electronic technology to improve both safety and economic performance and enable technological developments to take place within an overall safety framework.
IEC 61508 provides you with system-based approach, with sufficient flexibility for the future, provide a risk-based approach for determining the required performance of safety-related systems, and provides a generically based standard that can be used directly by industry but can also help with developing sector standards (e.g., machinery, process chemical plants, medical or rail) or product standards (e.g., power drive systems),
PD IEC/TS 61508-3-1 contain a complete description of the conditions of use of the pre-existing software and help to reuse the pre-existing software when reusing software for SIL 1 and SIL 2.
IEC TS 61508-3-1:2016