Pepperl+Fuchs KFD2-STC4-Ex Series - Characteristic Safety Values

2014-09
10
Safety Manual SIL KFD2-ST*4-(Ex)*, KFD2-CR4-(Ex)*
Planning
2.4 Characteristic Safety Values
KFD2-CR4-(Ex)1, KFD2-STC4-(Ex)1, KFD2-STC4-(Ex)1-3, KFD2-STC4-(Ex)1-Y*,
KFD2-STV4-(Ex)1-1, KFD2-STV4-(Ex)1-2
Parameters acc. to IEC 61508 Values
Assessment type FMEDA report
Device type A
Demand mode Low Demand Mode or High Demand Mode
Safety function
2
Transfer of analog values
HFT 0
SIL 2

s
192 FIT

dd
1
118 FIT

du
36 FIT

no effect
2
192 FIT

not part
212 FIT

total (safety function)
346 FIT
SFF 89 %
MTBF
3
204 years
PFH 3.60 x 10
-8
1/h
PFD
avg
for T
proof
= 1 year 1.58 x 10
-4
PFD
avg
for T
proof
= 2 years 3.15 x 10
-4
PFD
avg
for T
proof
= 5 years 7.88 x 10
-4
1
"Fail high" and "Fail low" failures are considered as dangerous detected failures 
dd
.
2
"No effect" failures are not influencing the safety functions and are therefore added to the 
s
.
3
acc. to SN29500. This value includes failures which are not part of the safety function.
Table 2.2
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