One of our controls experts offered this follow-up off-list: 1. - What is the principle of tuning in the Foxboro PIDE & PIDA - is it load change or setpoint change or what? In both cases the tuning parameters are calculated to maximise load rejection. Furthermore the PIDA block features take the tuning one step forward by allowing a second degree of freedom in the controller to be adjusted to shape a non-overshooting response to a setpoint step change. 2. - What is the underlying difference between PIDA & PIDE in terms of auto tuning methodology? Upon measuring damping and overshoot error signal, and the period of oscillation the PIDE uses heuristic rules to adjust the controller parameters to give the specified damping and overshoot. In the PIDA-FBTUNE retuning is based on restoring robustness margins and performance. Expert rules are used when the control error is not oscillatory or when oscillations are limit cycles or externally forced. 3. - Does Foxboro have model-based tuning techniques? Yes, we do have model based tuning techniques available for the PID controller modes tuning. 4. - How do we configure a simple auto-tuner using PIDE & FBTUNE? The PIDE selftuning algorithm is enabled by the parameter STNREQ. The FBTUNE block works in junction with the PIDA block thru the parameter PIDBLK. Additional comments: Foxboro offers in depth training on these subjects. In addition to the training, Foxboro is currently offering loop optimization and loop performance monitoring services the customer may be interested in. Regards, Alex Johnson Invensys Systems, Inc. 10900 Equity Drive Houston, TX 77041 713.329.8472 (voice) 713.329.1700 (fax) 713.329.1600 (switchboard) alex.johnson@xxxxxxxxxxxxxxxx -----Original Message----- From: foxboro-bounce@xxxxxxxxxxxxx [mailto:foxboro-bounce@xxxxxxxxxxxxx] On Behalf Of nurul izzah Sent: Tuesday, March 28, 2006 9:28 PM To: foxboro@xxxxxxxxxxxxx Subject: [foxboro] PIDE & PIDA Dear List, Our process engineer shoot the following questions to us early in the morning today. I must admit, my knowledge on the the following topic is quite sketchy. Appreciate if the list could shed some light and/or point me to the literatures that can explain the following: - What is the principle of tuning in the Foxboro PIDE & PIDA - is it load change or setpoint change or what? - What is the underlying difference between PIDA & PIDE in terms of auto tuning methodology? - Does Foxboro have model-based tuning techniques? - How do we configure a simple auto-tuner using PIDE & FBTUNE? And yes, she did read the Focdoc :) Best regards, Nurul Izzah _______________________________________________________________________ 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