Terms And Definitions - turck IM1-12-R Handbuch

6 Terms and Definitions

FIT
FMEDA
HFT
Low demand mode
PFD
AVG
SFF
SIF
SIL
Type A component
T[Proof]
© exida.com GmbH
Stephan Aschenbrenner
more@turck.com • www.turck.com • 2015/04
Anhang – EXIDA-Report FMEDA Turck 04/07-14 R002
Failure In Time (1x10 -9 failures per hour)
Failure Modes, Effects, and Diagnostic Analysis
Hardware Fault Tolerance
Mode, where the frequency of demands for operation made on a safety-
related system is no greater than one per year and no greater than twice
the proof test frequency.
Average Probability of Failure on Demand
Safe Failure Fraction summarizes the fraction of failures, which lead to a
safe state and the fraction of failures which will be detected by
diagnostic measures and lead to a defined safety action.
Safety Instrumented Function
Safety Integrity Level
"Non-complex" component (all failure modes are well defined); for
details see 7.4.3.1.2 of IEC 61508-2.
Proof Test Interval
TURCK 04-07-14 R002 V3R0.doc; February 21, 2014
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