Re: [foxboro] Measuring Overall System Reliability

Ditto here.  Our system has been down only once since 1990 and that was
because of flooding when we abandonded our facility.  Only FBM failures
were when doing a CP reboot after a major upgrade (never while on line).
 Lost two analog channels on separate FBM since 1990.  Regarding
filedbus issues, we experienced fieldbus errors and found the length of
a FT pair had to be very close.  So we just disable automatic switching
and let it switch if there is a failure.  This has resolved our fieldbus
problems.  Our goal IS 100% uptime.   We have achieved just under  than
99.9900%

The magic of Nines
Availability     Downtime/Yr
90.0000%     37 days
99.0000%     3.7 Days
99.9000%     8.8 Days
99.9900%     53 minutes
99.9990%     5.3 minutes
99.9999%     32 seconds


>>> Hank.Matic@xxxxxxxxxxxxxxx 6/16/2004 4:31:29 AM >>>
We've been running Foxboro I/A here since 1990 , with only one major
upgrade
for the y2k fiasco. At that time we replaced our CP10's with CP30's ,
our
AP20's with AW51E's , our PW's with AW51B's , our WP20's with WP30's
and
WP51B's. With the original hardware the highest failures we had were
on
WP20's especially when they were rebooted. The minor failures we have
had on
FBM's ( usually single piont failures ) were due to events out in the
field
rather than the hardware itself. We experienced a small failure rate on
the
FBM's when we did EEPROM updates and we had an AW51E fail in infantcy.
Thru
all of that we never experienced any down time on our units due to the
I/A
system. Our other plants have WGH systems , 2 of the plants that use
the DCS
for controls have had significant failures which caused one plant to
go
offline , and caused some signifiacnt damage at the other. All in all
I'm
happy with I/A although I wouldn't recommend the Microsoft version to
anyone.
 
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Process
Systems (formerly The Foxboro Company). Use the info you obtain here
at
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_______________________________________________________________________
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Systems (formerly The Foxboro Company). Use the info you obtain here at
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
 
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