Re: [foxboro] fbm failed messages
- From: dirk.pauwels@xxxxxxxxxx
- To: foxboro@xxxxxxxxxxxxx
- Date: Mon, 27 Jun 2011 16:56:46 +0200
Hi Tom and Corey,
I guess I can safely assume the FBM's were still OK then, Usually it takes
a few minutes to recover, this time it took more than 30 minutes, so i
assumed the FBM really failed. I'll rely on the ECBSTA to indicate a
failed FBM rather than sysmon then.
I'll do some more testing with the ECBSTA, because we do not have a safety
plc and we rely on certain valves and motors to be available in case of
emergency. If the FBM is failed at the time, sofar for emergency..... If
we know it failed we can take immediate action
Kind regards
Dirk
wrote
We still see it too, and we do not have any FBMs running ladder logic. We
did the isolated-DIN-rail hack that Foxboro recommended but that didn't
help.
The problem seems to lie in the coax cabling, or the CP's implementation
of it**. The best solution for us so far has been to use fiber in the
fieldbus network as much as possible. On the installations where we
connect the thin white coax from the elevator plugs directly into a fiber
converter (the newer Black Box one, not the crappy 1st-gen model that
Foxboro initially offered), we see few if any of these errors.
Corey Clingo
BASF Corp.
**Side note: anyone who has ever worked with any kind of coax cable
networking knows it's finicky, and I still am incredulous that Foxboro
chose to use it when 10baseT (and maybe even 100baseT) was commonplace.
From:
tjvandew@xxxxxxxxx
To:
foxboro@xxxxxxxxxxxxx
Date:
06/27/2011 09:18 AM
Subject:
Re: [foxboro] fbm failed messages
Sent by:
foxboro-bounce@xxxxxxxxxxxxx
We saw the intermittent failure and module switch over from fieldbus A to
B to A... Also. It appeared to be more prevalent on FBM's running ladder
logic, presumably because of increased data load of passing IFL's and
OFL's as well as CIN's and COUT's across the fieldbus. If you force the
fieldbus to stay on one bus, like A ONLY, the error messages will cease
but then you give up bus redundancy for all FBM's attached. If you leave
it on two busses it will constantly switch when it hits a COMM ERROR. On
one bus it will retry on that bus and doesn't send an error unless it has
multiple consecutive failures on that bus. Solution, live with the errors
and bus switching or run on one bus only. I don't think Foxboro ever
really solved this problem. How about it Dave Caldwell, is this still an
issue for you?
Tom Vandewater
Sent from my Verizon Wireless BlackBerry
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