PID Disturbance Rejection of the Gravity Drained Tanks

In previous posts we explored disturbance rejection in the gravity drained
tanks process using P-Only and then PI control. In the PI study, we
confirmed the observations we had made in the PI control of the heat
exchanger investigation.

In particular, we learned that PI controllers can eliminate the offset
associated with P-Only control, have integral action that increases the
tendency for the PV to roll (or oscillate), have two tuning parameters that
interact, making it challenging to correct tuning when performance is not
acceptable. Here we investigate the benefits and challenges of derivative
action and PID control when disturbance rejection remains our control
objective...
 
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   http://www.controlguru.com/2006/p122006.html
 
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for Automatic Process Control" are available as links from:
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Best wishes in this holiday season,

Doug Cooper