This part of IEC 61511, which is a Technical Report, specifies the rationale behind all clauses and the relationship between them, raises awareness for the most common misconceptions and misinterpretations of theclauses and the changes related to them, explains the differences between Ed. 1 and Ed. 2 of IEC 61511-1 and the reasons behindthe changes, presents high level summaries of how to fulfil the requirements of the clauses, and explains differences in terminology between IEC 61508-4:2010 and IEC 61511-1 Ed. 2.