586 / 1143
17
So would the certificate pass using IEC61511 Ed 2?
§
Report is still 10 years old
§
Report still based on data for much old version
of installed device
§
Requirements for data used in PFDavg
calculations to be based on reliability data from
similar operating environment’
§
Requirement for control of systematic failures,
again demonstrating the performance of the
device in
similar operating environments
§
Likely that the certificate would be rejected again
©ABBGroup
October23,2016|Slide33
©ABBGroup
October23,2016|Slide34
How did we solve the problem?
§
I went back to the SFF calculation
§
Investigated what dangerous failures were not detected by
the diagnostics
§
Looked at other checks that were being performed before
ship offloaded
§
Did these checks increase the proportion of dangerous
detected faults?
§
Increased
λ
DD
and decreased
λ
DU
§
SFF raised above 90% threshold
λ
SU
+ λ
SD
+ λ
DD
SFF =
λ
SD
+ λ
SU
+ λ
DD
+ λ
DU