Re: [foxboro] CP60 and FBM legacy
- From: Corey R Clingo <clingoc@xxxxxxxxxxxxx>
- To: foxboro@xxxxxxxxxxxxx
- Date: Fri, 21 Oct 2005 10:35:37 -0500
I think so. So you are saying that the CP sends out a notification for
the FCMs/DCMs to poll the FBMs on the legacy fieldbus(es) for data, waits
a bit (or maybe not), and then sends out a "do you have the data yet?"
message to each pair in turn. If the FCM/DCM pair in question is not
ready with the FBM data, the CP waits (or hopefully goes on to ask the
next FCM/DCM pair) and then retries the one that wasn't ready last time
around.
Does this also imply that ECBs for 100-series FBMs ought to be grouped by
FCM/DCM as well, or listed in order below the ECB for their respective
FCM/DCM pair, or does the CP automatically "know" what FBMs belong to what
FCMs/DCMs and optimize the polling?
Corey
"Johnson, Alex P (IPS)" <alex.johnson@xxxxxxxxxxxxxxxx>
Sent by: foxboro-bounce@xxxxxxxxxxxxx
10/21/2005 10:14 AM
Please respond to foxboro
To: foxboro
cc:
Subject: Re: [foxboro] CP60 and FBM legacy
Order of the DCM/FCMs also matters to leverage the parallelism.
You should list the ECBs for the FCM/DCMs in order by most FBMs "beneath"
them, i.e., shorter chains first.
The CP sends out a message across the set of FCM/DCMs. Then it comes back
an
queries them in the order that they are listed in the ECB compound. If the
FCM/DCM is not ready, the CP waits and retries.
Thus, putting the short chains first will yield the best results because
it
leaves time for the longer chains to process.
Make sense?
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
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