Knick ProLine P22400 Mode D'emploi page 29

SIL Safety Manual
Load > 700 Ω (e.g., operation as repeater power supply)
Characteristic Value
103.2 FIT 1)
λ total
λ S 94.2 FIT
λ D 9 FIT
λ DU 9 FIT
λ SD 0 FIT
λ DD 0 FIT
SFF 91.3 %
0 % (no diagnostics) 2)
DC
221 years 3)
MTTF D
CAT 1 (1oo1) or 3 (1oo2)
PL c (1oo1) or e (1oo2)
SIL 3
MTTR 72 h max. time to repair
Temperature Max. 40 °C
PFH/PFD Values
PFD 1oo1
PFH 1oo1
(1/h)
PFD 1oo2
PFH 1oo2
(1/h)
1)
FIT = failure per 10
2)
Diagnostic coverage: DC = λ DD/( λ DU + λ DD)
3)
Worst-case calculation for high or continuous demand rate. After 8 to 12 years, the failure
rates of the electronic components will increase, whereby the derived PFD and PFH values
will deteriorate (IEC 61508-2, Edition 2.0, 7.4.9.5, note 3).
T 1 =1 a
4 x 10 -5
(4 %)
9 x 10 -9
(9 %)
4 x 10 -7
(0.4 %)
9 x 10 -10
(0.9 %)
T 1 = Time interval between the functional tests of the safety function
% values in brackets = proportion of maximally permitted PFD or PFH value for SIL 3.
9
hours
Explanation
Total failure rate
Rate of safe failures
Rate of dangerous failures
Rate of dangerous undetected failures
Rate of safe detected failures
Rate of dangerous detected failures
Fraction of non-hazardous failures
Mean operating time until dangerous failure
Category according to EN 13849-1
Performance level according to EN 13849-1
Safety integrity level according to EN 61508
Replacing a defective device by a replace-
ment device of the same model
Long-time average temperature
T 1 =2 a
7.9 x 10 -5
(7.9 %)
9 x 10 -9
(9 %)
7.9 x 10 -6
(0.79 %)
9 x 10 -10
(0.9 %)
29
T 1 =3 a
1.2 x 10 -4
(11.9 %)
9 x 10 -9
(9 %)
1.2 x 10 -6
(1.2 %)
9 x 10 -10
(0.9 %)