6 Change impact analysis for other safety standards
The safety analysis reported in this safety manual is executed according to the IEC 61508 safety norm. This
section reports the outcome of a change impact analysis with respect to different safety standards. For each new
safety standard addressed, the following items are considered:
• Differences in the suggested hardware architecture (architectural categories), and how to map to safety
architectures of IEC 61508.
• Differences in the safety integrity level definitions and metrics computation methods, and how to recompute
and judge the safety performances of the devices according to the new standard.
The safety standards examined within this change impact analysis are:
• ISO 13849-1:2015, ISO13849-2:2012 – Safety of machinery and Safety-related parts of control systems,
• IEC 62061:2005+AMD1:2012+AMD2:2015 – Safety of machinery and Functional safety of safety-related
electrical, electronic and programmable electronic control systems,
• IEC 61800-5-2:2016 –Adjustable speed electrical power drive systems – Part 5-2: Safety requirements –
Functional
6.1 ISO 13849-1:2015, ISO 13849-2:2012
ISO 13849-1 is a type B1 standard. It provides a guideline for the development of Safety-related parts of
machinery control systems (SRP/CS) including programmable electronics, hardware and software.
6.1.1 ISO 13849 architectural categories
ISO 13849-1:2015 reports in section 4.4, Figure 4 a typical safety function diagrammatic presentation. Under the
assumption that Compliant item as defined in section is used to implement the b (logic), the equivalence of the
ISO 13849 representation with the one in Section 3.2.1 is evident. The mapping of ISO 13849 architectures with
the one described in Section 3 is possible.
ISO 13849-1:2015 in section §6 defines in details five different categories. The following table lists for each
category the possible implementation by one of the IEC 61508 compliant architectures described in this manual
in Section 3 . It is worth to note that for each category, the achievable PL is decided by the specific values of
diagnostic coverage (DC)
avg
and mean time to dangerous failure (MTTFd) (refer to Section 6.1.2 for details on
computations).
UM2305
Change impact analysis for other safety standards
UM2305 - Rev 10
page 96/110
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