Safety Manual SIL KCD2-SR-(Ex)*(.LB)(.SP), HiC282*
Planning
2
014-
09
9
Reaction Time
The reaction time for all safety functions is < 20 ms.
2.4
Characteristic Safety Values
The characteristic safety values like PFD, SFF, HFT and T
proof
are taken from the
SIL report/FMEDA report. Please note, PFD and T
proof
are related to each other.
The function of the devices has to be checked within the proof test interval
(T
proof
).
Note!
The failure outputs are not safety relevant.
Parameters acc. to IEC 61508
Values
Assessment type and
documentation
Full assessment
Device type
A
Mode of operation
Low Demand Mode or High Demand Mode
HFT
0
SIL
2
Safety function
One relay output of one channel
Two relay outputs of a one
channel device in series
s
189 FIT
216 FIT
dd
18 FIT
48 FIT
du
47 FIT
45 FIT
no effect
89 FIT
90 FIT
total (safety function)
254 FIT
309 FIT
not part
58 FIT
58 FIT
SFF
81.55 %
85.4 %
MTBF
1
365 years
311 years
PFH
4.68 x 10
-8
1/h
4.51 x 10
-8
1/h
PFD
avg
for T
proof
= 1 year
2.05 x 10
-4
1.97 x 10
-4
PFD
avg
for T
proof
= 2 years
4.10 x 10
-4
3.95 x 10
-4
PFD
avg
for T
proof
= 5 years
1.02 x 10
-3
9.86 x 10
-4
Reaction time
2
< 20 ms
1
acc. to SN29500. This value includes failures which are not part of the safety function.
2
Time between fault detection and fault reaction.
Table 2.3
