Functional Safety HiD2030(SK)
Planning
20
21
-0
9
13
3.4
Characteristic Safety Values
The characteristic safety values like PFD, PFH, SFF, HFT and T
1
are taken
from the FMEDA report. Observe that PFD and T
1
are related to each other.
The function of the devices has to be checked within the proof test interval (T
1
).
Parameters
Characteristic values
Assessment type and documentation
Full assessment
Device type
A
Mode of operation
Low demand mode or high demand mode
HFT
0
SIL
2
SC
3
Safety function
Transfer of the analog signals
s
1
109 FIT
dd
68 FIT
du
51.9 FIT
total (safety function)
1
1
"No effect failures" are not influencing the safety function and are therefore not included in the SFF and the safety values
of the safety function.
229 FIT
not part
182 FIT
SFF
1
77.35 %
MTBF
2
2
acc. to SN29500. This value includes failures which are not part of the safety function/MTTR = 8 h.
The value is calculated for one safety function of the device.
190 years
PFH
5.19 x 10
-8
1/h
PTC
100 %
PFD
avg
for T
1
= 1 year
2.27 x 10
-4
PFD
avg
for T
1
= 2 years
4.54 x 10
-4
PFD
avg
for T
1
= 5 years
1.14 x 10
-3
Fault reaction time
3
3
Time between fault detection and fault reaction
< 10 ms
Table 3.3
