BS EN ISO 13849-1-2006标准

of the safety function depends on several factors, including hardware and software structure, the extent of fault detection mechanisms [diagnostic coverage (DC)], reliability of components [mean time to dangerous failure (MTTF d), common cause failure (CCF)], design process, operating stress, environmental conditions and operation procedures. In order to assist the designer and help facilitate the assessment of achieved PL, this document employs a methodology based on the categorization of structures according to specific design criteria and specified behaviours under fault conditions. These categories are allocated one of five levels, termed Categories B, 1, 2, 3 and 4. EN ISO 13849-1:2006 Licensed Copy: AUB User, na, Tue Oct 23 07:07:22 GMT+00:00 2007, Uncontrolled Copy, (c) BSI