[foxboro] Device diagnostic info via FBM223 (was: Mixing 100-series and 200 series FBMs on one CP60)

Alex, Corey, Dirk, Kevin, and all the others who responded to my question: 

Thank you very much for the help on the issue of mixing FBM types. I think
the issues are becoming a lot clearer. We are most probably over-cautious
with putting our FBM223 on a separate CP60, but our plant is meant to go
down only once every year or two, so we have to make sure there are no
problems affecting the rest of the system when we start up our new
Profibus-based controls.

I have one question for people who have used FBM223 to communicate to
instrumentation: do any of you know whether it is possible to query devices
for diagnostic information from the Foxboro I/A by using acyclic calls?
Generally a PC system is connected onto the Profibus network to function as
a Class 2 Master, from which one can configure the devices and retrieve
diagnostic information. Quite a few suppliers offer these PC-based systems.
But apparently these acyclic calls can also be made from Class 1 Masters
(typically PLCs and DCSs) by using the GET-DIAG message. Does this exist on
the Foxboro I/A? If it does, how does one implement it?

Just to clarify: I can read the data and the status information using
standard RIN and IIN blocks on the Foxboro. These set up cyclic connections
to the individual devices, which ensure that the values are updated at the
set interval. The status data is a bit limited in its usefulness, though, so
I would prefer to get the additional diagnostics string back as well. If I
can do it with a (slow) cyclical command, that would be fine too.

Regards,

Joachim Schubert
Falconbridge Ltd, Canada


-----Original Message-----
From: Johnson, Alex P [mailto:alex.johnson@xxxxxxxxxxxxxxxx]
Sent: 2005-Jul-08 18:05
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] Mixing 100-series and 200 series FBMs on one CP60


The comments made so far are accurate:

1) Mixing FBM types is not really the issue; it works.
2) Items that impact I/O loading include:
   a) The number of FBMs under an FCM (and all devices called 
      FCM/DMC/FBI10e are FCMs) - more is better
   b) The number of FBMs per FCM has an indirect impact. 
      i) The longer chains need more time for the FCM time to get
         its data and prevent the CP from having to retry to get it.
      ii)The order of the ECBs does determine the order in which 
         the FCMs are queried.   
   c) The use of DCI blocks and the FBMs that they talk to 
      will increase loading more than you might expect.
4) No more than 32 FBMs per FCM is good advice
5) There is/was a defect in LL processing that could cause problems.

Hope this summary helps.


Regards,
 
Alex Johnson
Invensys Systems, Inc.
10707 Haddington
Houston, TX 77063
+1 713 722 2859 (voice)
+1 713 932 0222 (fax)
+1 713 722 2700 (switchboard)
alex.johnson@xxxxxxxxxxxxxxxx
 
 
_______________________________________________________________________
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: