Re: [foxboro] Hart FBM's
- From: Harshad Viradia <harshad_viradia@xxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Wed, 25 Aug 2010 02:12:28 -0700 (PDT)
We found similar problem of measurement elevation in 2007 and we had production
loss many times till March 2010 because of the trips occurred due to elevation,
we installed the QF which doesn't address the root cause but at least it
suppress the elevation.
________________________________
From: "DUNHAM, KENNETH J" <kdunham@xxxxxxxx>
To: "foxboro@xxxxxxxxxxxxx" <foxboro@xxxxxxxxxxxxx>
Cc: "SWAN, MICHAEL" <mswan@xxxxxxxx>; "STEINKE III, JOHN W"
<jwsteinke@xxxxxxxx>; "DUNHAM, KENNETH J" <kdunham@xxxxxxxx>
Sent: Wed, August 25, 2010 12:13:02 AM
Subject: Re: [foxboro] Hart FBM's
Sheldon,
Re: I would be interested to lean who the other customers were that experienced
this A/D Gain, and how their systems were affected. And why an advisory
bulletin was never issued. Foxboro??
I can't answer that last part but we had a failure of FBM 214 executing a
step-jump of about 25% in December 2008. The issue only impacts 214's using
current input.
We are a CE Pressurized Water Reactor nuclear generating station.
This resulted in an excursion of our Steam Generator Water Level and
considerable operator confusion/concern. Normal control was restored when we
bypassed the affected channel (dual level inputs). Since in our case, the step
change did NOT exceed 100% input, the control system sensed a channel - to -
channel deviation and defaulted to manual control, which it was designed to do
(had the input exceeded 102%, it would have been declared "bad" and reverted to
the remaining 'good' input).
We implemented the QF for CAR 1009770 at the time and updated the EEPROM image
to 2.40C, which is the version currently installed.
It concerns me that you had this happen on 2.40D. I will have to look into
QF1013828.
We have not had any other FBM 214 issues to date but then again, we don't have
very many (4).
Item Number
3.4
Title:
Quick Fix for CAR 1009770
Date: 09/30/08
CAR Number
CAR#1010386, HPS#17187
Quick Fix Number
QF1009770
Description:
Reports from 3 customer sites indicated that FBM214's would sometimes
shift all current signals upward by 20-30%. This was investigated and a
potential exists for this to happen if the AI background process didn't
have enough time to finish up before it was time to take another sample.
This problem was only seen on the FBM214's at site, not with the FBM216's.
(CAR#1010386 HPS#17187)
FCS Applicability Discussion
This item appears to be the exact failure experienced by FCS. There is no
record of Invensys notification to FCS of this potential problem. This OE was
discovered when specifically looking through the Foxboro database for a similar
failure.
Feel free to contact me off-line if you need more info.
Kenneth Dunham
ERF/DCS System Engineer,
Fort Calhoun Station
9610 Power Lane, Blair, NE 68008
Mail Stop FC 1-9
Phone: (402) 533-6934
email: kdunham@xxxxxxxx<mailto:kdunham@xxxxxxxx>
Good judgement comes from experience.
Experience comes from bad judgement.
(Author Unknown)
-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On
Behalf Of sssmith1@xxxxxxx
Sent: Tuesday, August 24, 2010 11:41 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] Hart FBM's
Corry,
We have experience similar "infant mortality" problems with FBM214 TA's
during recent commissioning. I believe we had 2 such failures. None
since.
Technician wrote up the below technote capture for future diagnostics of
similar occurrences in house.
During Foxboro Controls installation and testing, we experienced loss of
control on a piece of equipment utilizing 4-20ma current loop of an
FBM214. Hart communication in this instance is only utilized for a
feedback indication. Upon discovery of this malfunction, we replaced the
suspected FBM module with a new one with no change of symptoms noted.
Further investigation led us to suspect that the problem was in the FBM214
Termination Assembly. Utilizing a digital ohmmeter, we checked the
resistance readings across terminals ?A? and ?C? of each input. It was
discovered that the input in question read approximately 80K-120K Ohms, as
compared to a normal reading of 8+Megohms on known good inputs. Readings
were taken with the module deenergized and field wiring lifted. We then
replaced the TA, and the problem was solved.
We have experience other HART FBM issues as well.
Most recently, last week we encountered issue where ALL CURRENT values
from a FBM 214 ( EEPROM version 2.40D ) experienced an abrupt gain across
all channels of approximately 20-30 percent.
Foxboro TAC told us that this was a known issue ( No technical advisory
bulletin ever issued??????)
A EEPROM new EEPROM update was released on Friday last week (QF1013828)
that is supposed to partially address the issue. They still don't know,
and I don't believe have been able to replicate the problem in house, but
this has occurred at 4 customer sites. This could have been a very
catastrophic event, but fortunately, our IO and logic was partitioned and
segmented in such a way that disaster was averted.
We exclusively use CURRENT from the HART channels for control. Do not
poll HART signals. for RIN's. We do use RIN HART PV signals against our
215 hart AO's for deviation alarm purposes though.
During the HART AI gain event, the HART PV signal was unaffected, as
confirmed at the transmitter, via 375 hand held, and by PACWare
interrogation.
Scary to say the least.
I would be interested to lean who the other customers were that
experienced this A/D Gain, and how their systems were affected. And why
an advisory bulletin was never issued.
Foxboro??
Sheldon Smith
Office:972-884-2843
Cell: 214-460-4073
EFax: 866-734-2905
Conf: 877-253-4307 #7082843
Mailto: sssmith1@xxxxxxx
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Systems (formerly The Foxboro Company). Use the info you obtain here at
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_______________________________________________________________________
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
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