Pepperl+Fuchs KFD2-UT2 Series, Manual

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Functional Safety KFD2-UT2-(Ex)*(-1)
List of Abbreviations
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0
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7 List of Abbreviations
ESD E mergency S hut d own
FIT F ailure I n T ime in 10
-9
1/h
FMEDA F ailure M ode, E ffects, and D iagnostics A nalysis

s
Probability of safe failure

dd
Probability of dangerous detected failure

du
Probability of dangerous undetected failure

no effect
Probability of failures of components in the safety loop that have
no effect on the safety function. The no effect failure is not used
for calculation of SFF.

not part
Probability of failure of components that are not in the safety loop

total (safety function)
Probability of failure of components that are in the safety loop
HFT H ardware F ault T olerance
MTBF M ean T ime B etween F ailures
MTTR M ean T ime T o R estoration
PCS P rocess C ontrol S ystem
PFD
avg
Average P robability of dangerous F ailure on D emand
PFH Average frequency of dangerous failure per hour
PLC P rogrammable L ogic C ontroller
PTC P roof T est C overage
SC S ystematic C apability
SFF S afe F ailure F raction
SIF S afety I nstrumented F unction
SIL S afety I ntegrity L evel
SIS S afety I nstrumented S ystem
T
1
Proof Test Interval
T
service
Time from start of operation to putting the device out of service