RE: Constraint Control - OutSel Block
Satish, The OUTSEL block is set up to handle reset windup & block initialization handling. It can be used where you have a normal PID loop that should be bumplessly interupted when a second controlled variable reaches a constraint target. Let's say you were normally operating with a fixed and steady gas flow to a vessel. In case the vessel pressure was getting close to the relief valve setting you decide that the normal feedrate must be cut. You set the SELOPT parameter to 2 for "Low" selection and add a second PID Pressure control loop with a setpoint somewhat below the relief valve setting. Properly configured: at the moment the pressure rises to the setpoint of the pressure controller the flow control valve will just start to close (from it's current position) and the loop will become a pressure controller with a minimum flow constraint. When the vapor removal rate from the vessel is increased the pressure controller will open the flow control valve until the flow setpoint is achieved and the flow controller will now bumplessly resume control of the valve. The SIGSEL block is possible but the OUTSEL block was built for this specific application. Many implementations are possible. Hope this answered your question. Rick Rys R2Controls --- This list is neither sponsored nor endorsed by the Foxboro Company. All postings from this list are the work of list subscribers and no warranty is made or implied as to the accuracy of any information disseminated through this medium. By subscribing to this list you agree to hold the list sponsor(s) blameless for any and all mishaps which might occur due to your application of information received from this mailing list. To be removed from this list, send mail to [EMAIL PROTECTED] with "unsubscribe foxboro" in the Subject. Or, send any mail to [EMAIL PROTECTED]
Constraint Control - OutSel Block
Hi, I am looking at details of constraint control in the I/A DCS. I have got the PSS and user doc of OutSel block from the Foxboro documentation which states that it can be used for constraint control. Can anyone help me out in getting additional info or refernce implementation! Thanks & Regards, Satish __ Do You Yahoo!? Get email alerts & NEW webcam video instant messaging with Yahoo! Messenger http://im.yahoo.com --- This list is neither sponsored nor endorsed by the Foxboro Company. All postings from this list are the work of list subscribers and no warranty is made or implied as to the accuracy of any information disseminated through this medium. By subscribing to this list you agree to hold the list sponsor(s) blameless for any and all mishaps which might occur due to your application of information received from this mailing list. To be removed from this list, send mail to [EMAIL PROTECTED] with "unsubscribe foxboro" in the Subject. Or, send any mail to [EMAIL PROTECTED]
