Functional Safety SJ2-SN, SJ3,5-S(1)N
Planning
2
01
9-
12
13
To ensure the safety of the safety loop according to SIL 3, only use control units
for SIL 3 safety applications from Fuchs, i. e. switch amplifier KFD2- SH-Ex1.
Reaction Time
The reaction time for all safety functions is < 1 ms.
3.4
Characteristic Safety Values
The characteristic safety values like PFD, SFF, HFT and T
1
are taken from
the SIL report/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
).
Note
See corresponding datasheets for further information.
Parameters
Characteristic values
Assessment type and
documentation
FMEDA report with proven-in-use assessment
1
1
For the proven-in-use demonstration, sales figures, customer returns and questionnaires filled out by customers were used
which show that no unknown systematic faults are expected. The device is based on a former device that was evaluated
for a proven-in-use statement by exida.com GmbH.
Device type
A
Mode of operation
Low Demand Mode or High Demand Mode
HFT
0
Safety function
High impedance state, depending on the position of the measuring plate
SIL (SC)
2 (3)
in combination with a control unit
according to EN 60947-5-6 (NAMUR)
3
in combination with a control unit
for SIL 3 safety applications from
Fuchs, i. e. switch amplifier
KFD2-SH-Ex1
s
2
2
"No effect" failures are not influencing the safety functions and are therefore included into the safe failures.
15.3 FIT
24.9 FIT
du
9.7 FIT
0.09 FIT
total (safety function)
25.0 FIT
25.0 FIT
SFF
61.3 %
99.64 %
PFH
9.67 x 10
-9
1/h
9 x 10
-11
1/h
PFD
avg
for T
1
= 1 year
4.24 x 10
-5
3.94 x 10
-7
PFD
avg
for T
1
= 2 years
8.47 x 10
-5
7.88 x 10
-7
PFD
avg
for T
1
= 5 years
2.12 x 10
-4
1.97 x 10
-6
MTTF
d
11800 years
Useful life time
20 years
Reaction time
3
3
Step response time, also valid under fault conditions (including fault detection and fault reaction)
< 1 ms
Table 3.2
