Re: [foxboro] NONLOP function

Please use the PIDA block and not the:

PID
PIDE
PIDX
PIDXE

blocks.

The PIDA does what the others do and much more.

Regards,
 
Alex Johnson
Invensys Process Systems
Invensys Systems, Inc.
10707 Haddington
Houston, TX 77043
713.722.2859 (voice)
713.722.2700 (switchboard)
713.932.0222 (fax)
ajohnson@xxxxxxxxxxx

-----Original Message-----
From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On
Behalf Of Brian Bates
Sent: Wednesday, January 19, 2005 9:35 AM
To: foxboro@xxxxxxxxxxxxx
Subject: Re: [foxboro] NONLOP function

Jaime

I use this to control the level of a tank, that has minor upsets in level
every 15 minutes when filters are backwashed.
When the backwash starts, the tank level starts to drop, and without the
NLOPT, the Prop. action would open the feed valve, which causes a swing in
the feed chemicals (not desirable). This configuration allows the
controller to (almost) ignore the backwash upsets.

The controller is configured as follows: NONLOP = 1, HZONE = 0.2, LZONE =
0.2, and KZONE = 0.1 (PBAND = 100).

When the spt deviation is between +0.2, and - 0.2, the controller gain is
(1.0 X 0.1) = 0.1 (1,000% PB).
If the error is larger than + or - 0.2, the gain is 1 (100% PB).

It is confusing because Foxboro uses PB for setting controller gain, and
the KZONE is a gain factor, so you must convert PB to gain to calculate the
effect of your chosen KZONE.

      -Regards, Brian Bates.




 

                      "Jaime Claramunt

                      R. (Inforsa)"            To:
foxboro@xxxxxxxxxxxxx                                                
                      <jclaramunt@infor        cc:

                      sa.cmpc.cl>              Subject:  [foxboro] NONLOP
function                                            
                      Sent by:

                      foxboro-bounce@fr

                      eelists.org

 

 

                      01/19/2005 11:24

                      AM

                      Please respond to

                      foxboro

 

 





Hi List,

Does anybody knows how to work with NONLOP option on PIDXE block ?
Manuals are a little bit confusing...about HZONE and LZONE (percent of
span,
absolute value, of error,)
Do you have an actual case ?

Thx
Jaime Claramunt
INFORSA paper mill






 
 
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