Re: [foxboro] PID tracking question
- From: prakash@xxxxxxxxxxxxxxx
- To: foxboro@xxxxxxxxxxxxx
- Date: Thu, 12 Jun 2003 08:31:18 +0800
Cyrus,
Does not sound like a problem with initialisation but a problem with
feedback. Check the FBK parameter of the controller and see if its
connected. Typically it should be connected to its output or to the output
of the SWCH.
Rgds,
Prakash K.K.
Process Control
Malaysia LNG Sdn Bhd.
"Cyrus W. Taft"
<cwtaft@compuserv To: Foxboro Mailing List
<foxboro@xxxxxxxxxxxxx>
e.com> cc:
Sent by: Subject: [foxboro] PID tracking
question
foxboro-bounce@fr
eelists.org
12/06/2003 05:44
AM
Please respond to
foxboro
I have a somewhat unusual control loop which uses an MDACT block as the
secondary controller in a cascade arrangement. Upstream of the MDACT blo=
ck
is a SWCH block to select between two different primary PID controllers. =
I
have a tracking problem on one of the PID controllers. When the problem=
PID is tracking, its output is what it needs to be for a bumpless transfe=
r
to the controlling mode. However, as soon as the transfer occurs, the
output of the controller drops to near 0.0. This then appears to put the=
downstream switch into a Hold mode but I am not sure of the exact sequenc=
e.
This is on an ESSCOR simulator at version 6.1. Any suggestions?
Also in troubleshooting this problem I noticed two parameters in the PID
block, INITI and INITO. I assume that these have something to do with
initialization but I can't find a mention of either one in the
documentation. I can change the INITI through the Select page but I am n=
ot
allowed to change the INITO. Can someone enlighten me on these parameter=
s?
Thanks for your help.
Cyrus Taft
EPRI I&C Center
_______________________________________________________________________
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: //www.freelists.org/list/foxboro
to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
_______________________________________________________________________
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: //www.freelists.org/list/foxboro
to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
Other related posts:
