Table of Contents
Advertisement
Functional Safety HiC283*
Planning
3.4
Characteristic Safety Values
Parameters
Assessment type and
documentation
Device type
Mode of operation
HFT
SIL
SC
1
MTBF
(HiC2831*)
1
MTBF
(HiC2832*)
PTC
Safety function
safe
dd
du
total (safety function)
3
SFF
PFH
PFD
for T
= 1 year
avg
1
PFD
for T
= 2 years
avg
1
PFD
for T
= 5 years
avg
1
4
Fault reaction time
Table 3.3
1
acc. to SN29500. This value includes failures which are not part of the safety function/MTTR = 24 h.
2
The device can be used in two modes of operation, inverse of mode operation and normal mode of operation.
3
"Annunciation failures" and "No effect failures" are not influencing the safety function and are therefor not included in the calculation
of the SFF.
4
The combined fault detection and fault reaction time is the time in which the device reacts to an occurred fault.
The characteristic safety values like PFD, PFH, SFF, HFT and T
from the FMEDA report. Observe that PFD and T
The function of the devices has to be checked within the proof test interval (T
14
Characteristic values
Full assessment
A
Low demand mode, high demand mode or continuous mode
0
2
3
154 years
120 years
99 %
Inverse mode of operation
106 FIT
3.3 FIT
26.8 FIT
136 FIT
80 %
-8
2.68 x 10
1/h
-4
1.28 x 10
-4
2.56 x 10
-4
6.40 x 10
< 100 ms
2
Normal mode of operation
106 FIT
3.3 FIT
22.8 FIT
132 FIT
82 %
-8
2.28 x 10
1/h
-4
1.09 x 10
-4
2.18 x 10
-4
5.44 x 10
are taken
1
are related to each other.
1
2
).
1
Advertisement
Table of Contents
