Logic units to ensure safety functions

On 29 December 2009, application of the new Machinery Directive, 2006/42/EC, becomes mandatory. One of the associated changes concerns "logic units to ensure safety functions". These are now referred to in Annex IV of the directive. This product group is not precisely defined, however. Owing to the reference to these products in Annex IV of the Machinery Directive, stricter requirements apply to the conformity assessment procedure for application of the CE mark.

For the purpose of defining logic units to ensure safety functions, the IFA has made an article (PDF, 274 kB, non-accessible) available for download in which it classifies the components frequently employed in machine controls. The products concerned include safety PLCs (programmable logic controllers), power drive systems with integrated safety functions, safety switchgear, and any components for which the manufacturer states a Category, Performance Level or Safety Integrity Level. The classification of a component as a "logic unit to ensure safety functions" constitutes an estimation made by the IFA in liaison with other german test bodies. No responsibility is assumed for correctness.