Functional safety made easy

摘要

Continuing his current series on the European Machinery Directive 2006/42/EC, Dave Collier explains the most common jargon encountered when complying with the two new standards, BS EN ISO 13849-1 and BS EN 62061rnUnder the old standard, BS EN 954-1, the categories (B, 1,2, 3 and 4) dictated how a safety related electrical control circuit must behave under fault conditions. However, under the new European Machinery Directive 2006/42/EC, either of the two new standards can be followed: BS EN ISO 13849-1 or BS EN 62061 and these introduce the notion of not only if, but how likely, faults will occur.