Re: [foxboro] Setting Application Objects from IND blocks

Richard,=20

Sorry for the confusion.  Yes, we are using the mapping function for the
bulk of the control.  We just have one little piece of logic that
DMCplus can't handle that we are using IND blocks for.

We think we found the solution.  We were running the IND block with a
PERIOD of 30 seconds.  The block had a "WAIT 60" statement inside of a
do-loop, which we thought would take precedence over the block scan
period.  When we set the PERIOD parameter to 0.5 seconds, the block
behaved as we wanted it to with no latency.  Apparently, IND blocks run
only when their scan periods tell them to run, regardless of any
do-loops and WAIT statements inside the code.  I supposed we should have
assumed that to be true, but for some reason we thought the do-loop
inside the code took precedence.  Another lesson learned.  Thanks for
the responses.

Tim Lowell
Control Systems Engineer
ConocoPhillips Trainer Refinery
(610) 364-8362
tim.c.lowell@xxxxxxxxxxxxxxxxxx


-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx]
On Behalf Of Wetton, Richard J
Sent: Wednesday, November 17, 2004 5:38 PM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] Setting Application Objects from IND blocks

Tim,

I can not explain the latency, but have you tried using the map file
instead of the IND block's connectionless connection?   I would normally
try to use the aos mapping function in preference to the IND block,
because the IND block connection creates broadcast messages on every
read or write. The mapping function is looked after by foxapi and is far
more reliable than an IND block.

Richard Wetton.....

-----Original Message-----
From: Lowell, Tim: [mailto:Tim.C.Lowell@xxxxxxxxxxxxxxxxxx]=3D20
Sent: Thursday, 18 November 2004 5:44 AM
To: foxboro@xxxxxxxxxxxxx
Subject: [foxboro] Setting Application Objects from IND blocks


We are working on a DMCplus application where we have to set the values
of Application Objects, which were generated by DMCBridge, using an IND
sequence block.  We are noticing a great deal of latency, upwards of 1
or 2 minutes, between the time the IND sequence code runs and when the
Application Object value gets set.  Here is an example bit of IND HLBL
code:
=3D20

IF value1 > value2

            :APP_OBJ_CMPND:APP_OBJ.PARAM :=3D3D value3;

ENDIF

=3D20

Is this fairly typical of IND sequence code performance?  Is there
something special about Application Objects vs. regular CP blocks that
might cause this?  Is there a setting somewhere that maybe we have left
at the default that governs how fast AO's can be written to?

=3D20

Any ideas would be appreciated.

=3D20

Thanks,

=3D20

Tim Lowell

Control Systems Engineer

ConocoPhillips Trainer Refinery

(610) 364-8362

tim.c.lowell@xxxxxxxxxxxxxxxxxx

=3D20


=3D20
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