Hello all,
I've been having similar problems to the one Con has. If I read the docs
on PRI and PRO in a CALC block right, Niel's suggestion will help me in
about half of my problems (where I have multiple AOUTs but only use one at
a time, with a CALC block doing the switching and any characterization). I
am still having problems with controlling parallel downstream blocks
simultaneously from a single controller and managing initialization and
error propigation up and down the control stream, especially with CHARC
blocks downstream.
According to my documentation, the BCALCO on a CHARC block is supposed to
match measurement all of the time, whether PRIBLK is set or not, however
that is demonstratibly not the case. I'm down in Foxboro now, and was
hoping to find someone to fill me in on this Monday.
I also have not been able to set PRIBLK on a PID block (resident on a CP30)
when I have my AOUT on an AB-station. Anyone have any thoughts on this?
Kevin FitzGerrell
Fairbanks Gold Mining, Inc.
-------------original message-----------------------
Subject: Re:PRIBLK - Our special friend
Date: Fri, 24 Mar 2000 08:40:55 -0600
From: [EMAIL PROTECTED]
To: "O'Brien; Con (EUPRO)" <O'[EMAIL PROTECTED]>, "'Foxboro DCS mail
list'" <[EMAIL PROTECTED]>
Con,
I am not exactly sure of your question, but may this will help. We often use
CALC as fancy switch blocks to be able to switch which controllers can cascade
to one another. This requires PRIBLK parameters to be set in the normal manner
and back initialization parameters to be linked using the CALC block parameters.
Depending on which line-up is desired, the CALC block will jump to a certain
block of steps and then exit out. We use the PRI and PRO commands in the CALC
block to make all of the initialization things work correctly.
____________________Reply Separator____________________
Subject: PRIBLK - Our special friend
Author: "O'Brien; Con (EUPRO)" <O'[EMAIL PROTECTED]>
Date: 03/24/2000 10:10 AM
Good morning everyone!
After reading the postings of the last couple of days, I feel emboldened to
share some of my troubles with you all.
I'm trying to pass the "PRIBLK" initialization request and acknowledgment
bits between one controller and two output blocks. The application is a
split-range controller, with the PID output going through two CHARC blocks
to two AOUT blocks. I'm calculating the BCACLI input for the PID block
explicitly in a CALC block, using the BCALOs from the CHARC blocks.
This is straightforward enough, and normally I would do without the PRIBLK
functionality, because all blocks are running in one compound, at the same
period and phase. But unfortunately, the CHARC doesn't seem to recalculate
it's BCALCO unless PRIBLK is set.
I've come up with a way around, using dummy BIAS blocks to terminate the
initialization chains, but I would really like to be able to pass the BCALC
status bits from both CHARC blocks through to the PID.
Does anyone have a way of explicitly handling the initialization and
acknowledgment bits in a CALC block?
Many thanks,
Con O'Brien
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