Re: [foxboro] Short FBI Experience

Everyone knows that Foxboro, in the very generalest of terms, has been known to 
offer products more expensive than the "other" guy. Some of that is just plain 
old "over engineering". By that I mean, extra testing, constant design review 
and stringent standards. Some would call it "gilding the lily". You can see 
that in some of the instrument lines still in service today - SPEC200, 
SPECTRUM, yes and even the old 62H line. It's been demonstrated by John Peter 
Rooney's statistics that the MTBF for the original FBM is greater than 35 
years. In terms of the "bathtub curve", most installations are just slipping 
into the water. The cheering section has now left the building.
 
*K

        -----Original Message----- 
        From: tom.vandewater@xxxxxxxxxxxxxx 
[mailto:tom.vandewater@xxxxxxxxxxxxxx] 
        Sent: Tue 2/8/2005 6:16 PM 
        To: foxboro@xxxxxxxxxxxxx 
        Cc: 
        Subject: Re: [foxboro] Short FBI Experience
        
        

        Gaylon,
                We still have a bunch of the old style, (short) FBI's in 
service as
        well as the newer, (long), ones.  We also have a large installed base 
of the
        old, (short), FBM's that are of 1988/1989 vintage.  The form factor 
change
        happened with FBM's sometime around 1991-92 time frame and I thought it 
was
        more about better heat disipation than power issues, but I can't speak 
with
        authority on that.  I bet some of the Foxboro guys can answer why the 
design
        was changed. 
                We have had pretty good luck with all of the FBM's and FBI's in
        terms of reliability and have been tracking failure rates looking for a
        signal that tells us we are approaching end of life.  We had a lot of 
infant
        mortality in 1989-90 timeframe but since that time those modules have 
been
        quite reliable.  The past two times we have needed to do EEprom updates 
on
        the FBM's we have experienced increasingly higher failures to EEprom
        successfully and we see this as a potential end of life signal.  We have
        also experienced more failures during the very rare occasions that we 
power
        down the FBM's and then reapply power.
                We have just started a ten year upgrade plan to replace the 100
        series FBM's with 200 series because we know that all electronic 
components
        will eventually fail.  We feel that 16 years of continuous service is
        probably pushing it and it will cost us a bunch of money if we start 
having
        regular failures of IO, some of which will cause down-time.  Of course 
all
        of this also means that we will need to change out CP-30's and 40's to
        something that can talk to the 200 series IO and although we already 
have
        several CP-60's, I hate to spend new money on old technology so we will 
be
        moving to ZCP-270's and the MESH network ASAA.
        
        Tom VandeWater
        Control Systems Developer/Analyst
        Dow Corning Corporation
        Carrollton, KY   USA
        
        -----Original Message-----
        From: foxboro-bounce@xxxxxxxxxxxxx
        [mailto:foxboro-bounce@xxxxxxxxxxxxx]On Behalf Of Hicks, Gaylon F.
        Sent: Tuesday, February 08, 2005 4:58 PM
        To: foxboro@xxxxxxxxxxxxx
        Subject: [foxboro] Short FBI Experience
        
        
        Hi All,
        
        We have a system with several of the old "Short" style Field Bus
        Isolators (PN P0400VE-0F).  So far we have had good luck with these 1992
        era FBIs, but we have had one fail recently.  What I'm fishing for here
        is any experience with these old style FBIs, either good or bad, so we
        can determine if we need to look at replacing these any time soon.  I
        can't help the sneaking suspicion that there is something wrong with
        these old short FBIs that caused the change to the new style long FBI.
        I found a CAR #1000440 that suggests there were a few power problems
        with some of the old FBIs.
        
        Any information, insight, rumors, or outright speculation would be
        appreciated.
        
        Thanks,
        Gaylon Hicks
        TVA - Browns Ferry NP
        
        
        _______________________________________________________________________
        This mailing list is neither sponsored nor endorsed by Invensys Process
        Systems (formerly The Foxboro Company). Use the info you obtain here at
        your own risks. Read http://www.thecassandraproject.org/disclaimer.html
        
        foxboro mailing list:             http://www.freelists.org/list/foxboro
        to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
        to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
        
        
        
        _______________________________________________________________________
        This mailing list is neither sponsored nor endorsed by Invensys Process
        Systems (formerly The Foxboro Company). Use the info you obtain here at
        your own risks. Read http://www.thecassandraproject.org/disclaimer.html
        
        foxboro mailing list:             http://www.freelists.org/list/foxboro
        to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
        to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
        
        

-- No attachments (even text) are allowed --
-- Type: application/ms-tnef
-- File: winmail.dat


 
 
_______________________________________________________________________
This mailing list is neither sponsored nor endorsed by Invensys Process
Systems (formerly The Foxboro Company). Use the info you obtain here at
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
 
foxboro mailing list:             http://www.freelists.org/list/foxboro
to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave

Other related posts: