ABB LLT100 Functional Safety Manual page 16

Parameter
Systematic capability
hFT
Component type
Measuring mode
SFF
MTTr
MTBF
Diagnostic coverage
Diagnostic test interval
reaction time to process change
Measurement time interval
proof test effectiveness
—
Table 2 Failure rates
λ λ
s
355.6 FIT 706.3 FIT
—
Table 3
PFD
AVG
TI (years) 1
pFD 1.77 × 10
AVG
TI (years) 6
pFD 3.54 × 10
AVG
All safety related parameters are calculated using the Exida Electrical and Mechanical Component
Reliability Handbooks, 4th edition. The Exida environmental profile chosen for this FMEDA was Exida
Profile 2: Low Power Field Product. This environmental profile information is summarized in the table
below.
—
Table 4
Environmental profile summary
Profile according to Mean external
IEC 60654-1 temperature (°C)
C3 25
Considerations for High Demand Mode
In high demand mode, the end user shall comply with IEC61508-2 sections 7.4.5.3 and 7.4.5.4 for the
failure rates to be applicable.
If compliance to these specified sections is not met, the end user shall contact ABB (see back cover ot
this document) to calculate failure rates that are appropriate.
16
User Guide
Value
2
0
B
Low demand mode, high demand mode
90.4 %
24 h
69 years
λ / (λ
dd
<15 min
<1.5 s (with no damping or filtering)
<1.5 s
72 %
λ
dd du
113.3 FIT
2 3
2.12 × 10 2.48 × 10
–3 –3
7 8
3.91 × 10 4.26 × 10
–3 –3
Mean internal
temperature (°C)
30
+ λ ) ≈ 86.2 %
dd du
PFH
0.113 × 10
4 5
2.84 × 10 3.19 × 10
–3 –3
9 10
4.61 × 10 4.97 × 10
–3 –3
Temperature cycle
(°C/365 days)
25
failures/h
-6
–3
–3