Pepperl+Fuchs M-LB 5000 Series, Руководство пользователя

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Functional Safety M-LB-(Ex-)5000-System
List of Abbreviations
8 List of Abbreviations
PCS P rocess C ontrol S ystem
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

d
Probability of dangerous failure

no effect
Probability of failures of elements in the safety control 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 elements that are not in the safety control loop

total (safety function)
Safety function
HFT H ardware F ault T olerance
MTBF M ean T ime B etween F ailures
MTTF
d
M ean T ime T o dangerous F ailures
MTTR M ean T ime T o R estoration
PFD
avg
Average P robability of F ailure on D emand
PFH Average frequency of dangerous failure
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