User Documentation

Scope and standards
6 1373930000/02/06-2017
FMEDA (Failure Mode, Effects and Diagnostic
Analysis):
Systematic way to identify and evaluate the
effects of different component failure modes, to
determine what could eliminate or reduce the
chance of failure, and to document a system in
consideration.
Failure rates (λ):
λ
SD
, Total failure rate for safe detected failures
λ
SU
, Total failure rate for safe undetected failures
λ
DD
, Total failure rate for dangerous detected
failures
λ
DU
, Total failure rate for dangerous undetected
failures
MTTF (Mean Time To Failure):
Mean time between two failures. MTTF is a basic
measure of reliability for non-repairable systems.
Proof-test interval (T
proof
):
Interval between periodic tests performed to
detect failures in a safety-related system.