Pepperl+Fuchs HiC2081, Руководство пользователя

Страница: 30 / 32

2
018-
02
30
Functional Safety KCD2-UT2-(Ex)1, HiC2081
List of Abbreviations
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
PLC P rogrammable L ogic C ontroller
PTC P roof T est C overage
SFF S afe F ailure F raction
SIF S afety I nstrumented F unction
SIL S afety I ntegrity L evel
SIL (SC) S afety I ntegrity L evel ( S ystematic C apability)
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