14
LRG 1x-6x - Installation & Operating Manual -
819878-00
Reliability data as per EN 61508
Description
Characteristic values
Electrode type
LRG 1x-60
LRG 16-61
Safety integrity level
SIL 2
SIL 2
Architecture
1oo1
1oo1
Equipment type
Type B
Type B
Hardware error tolerance
HFT = 0
HFT = 0
Overall failure rate for dangerous undetected
failures
λ
DU
= < 20 * 10
-8
1/h
λ
DU
= < 35 * 10
-8
1/h
Overall failure rate for dangerous detected
failures
λ
DD
= < 5000 * 10
-9
1/h
λ
DD
= < 5000 * 10
-9
1/h
Safe failure fraction
SFF > 96.0 %
SFF > 95.0 %
Test interval
T1 = 1 year
T1 = 1 year
Probability of dangerous failure on demand
PFD < 100 * 10
-5
PFD < 160 * 10
-5
Diagnostic coverage. Percentage of dangerous
failures detected by a test.
DC > 95.0 %
DC > 91.0 %
Mean time to dangerous failure
MTTF
d
> 30 a
MTTF
d
> 30 a
Diagnostic interval
T2 = 1 hour
T2 = 1 hour
Performance level (as per ISO 13849)
PL = d
PL = d
Probability of dangerous failure per hour
PFH < 20 * 10
-8
1/h
PFH < 35 * 10
-8
1/h
Ambient temperature as a basis for calculation
Tu = 60 °C
Tu = 60 °C
Mean time to repair
MTTR = 0
(no repair)
MTTR = 0
(no repair)
Fraction of undetected dangerous failures that
have a common cause
beta = 2 %
beta = 2 %
Fraction of detected dangerous failures that
have a common cause
beta d = 1 %
beta d = 1 %
Fig. 4