[foxboro] Any suggested parameter settings for using PIDA with the Sample Readyfeature for composition control?




Does any one have parameter setting suggestions for using a PIDA controller
block for composition control on a distillation column when using the
Sample Ready mode?  I am not asking about the PBAND, INT, and DIR settings
as much as I asking about suggested ways to set up the PIDA block for
SAMPLING mode.

We currently have the PIDA block set as a PI controller and use the Sample
Ready feature.  The control is pretty good and there is a kick in the right
direction every time a new analyzer value is received, but because it is
operating in the periodic Sample Ready mode, the integral action appears to
be lacking - i.e. the controller seems to take a 1 shot action based on the
most recent change from setpoint, and does not seem to continue to try to
drive the measurement to setpoint.  When operating in the SAMPLING mode,
the PIDA Integral action is different from a controller operating in the
continuous mode.  The analyzer samples about every 32 minutes.


Neil Martin
Huntsman Polymers Corporation
2505 South Grandview
Odessa, TX.  79766
ph) 432-640-8436
pager)432-742-4289
email page)9157424289@xxxxxxxxxxxxxxxxxx

 
 
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