7. Glossary

DC ( Diagnostic Coverage )

Proportion of dangerous failures detected in relation to all dangerous failures.

LOPA

Layer Of Protection Analysis.

MooN

Structure for which a safety function is guaranteed when M out of N devices are in a condition to perform their function.

MTTR ( Mean Time To Repair )

Average time taken to repair a system.

SIL level

A discrete level (of four possible) for specifying the safety integrity requirements of the safety functions to be allocated to safety-related E/E/PE systems. Safety integrity level 4 has the highest degree of integrity; level 1 has the lowest.

Test period

Time between two tests...