Pepperl+Fuchs K-LB Series Manual page 34

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Application Examples
Combined with the characteristics for the surge protection barrier F*-LB-I the result is:
Total failure rate
MTBF
Safe failure rate
Dangerous undetected failure rate
Dangerous detected failure rate
SFF
Table 7.13 Sum of failure rates of Rosemount 3051S_C and surge protection barrier F*-LB-I
Derived from this results using equation 4:
T
1
PFD
avg
Table 7.14 PFD
The proof that the transmitter is still feasible for IEC/EN 61508 SIL 2 safety loops is done,
since SFF and PFD
34
1 year
-4
2.50 x 10
values of the combination of Rosemount 3051S_C and surge protection barrier
avg
F*-LB-I
values are still sufficient.
avg
536 FIT + 7 FIT = 543 FIT (rounded)
210 years
143 FIT
57 FIT
356 FIT + 7 FIT = 363 FIT (rounded)
89 %
2 years 5 years
-4
5.00 x 10 1.25 x 10
-4