BERTHOLD TECHNOLOGIES LB4710-080 - Page 30

Chapter 3 Functional Safety
Mini-Switch LB 471
30
Single channel architecture
HFT = 0 (Hardware Fault Tolerance)
PFD
avg
T
Proof
= 1 year
T
Proof
= 2 years
T
Proof
= 5 years
T
Proof
= 10 years
<0.036 x 10
-2
<0.073 x 10
-2
<0.180 x 10
-2
<0.360 x 10
-2
Two-channel architecture
HFT = 1 (Hardware Fault Tolerance)
1) for Common cause ß=5%
PFD
avg
T
Proof
= 1 year
T
Proof
= 2 years
T
Proof
= 5 years
T
Proof
= 10 years
<1.8 x 10
-5
<3.7 x 10
-5
<9.5 x 10
-5
<20 x 10
-5
2) for Common cause ß=10%
PFD
avg
T
Proof
= 1 year
T
Proof
= 2 years
T
Proof
= 5 years
T
Proof
= 10 years
<3.7 x 10
-5
<7.3 x 10
-5
<19 x 10
-5
<38 x 10
-5
Detector
Evaluation units
Container
Shielding with
source
Detectors
Evaluation units
Container
Shielding with
source