tag:blogger.com,1999:blog-76507495221458560992012-02-16T02:09:51.359-08:00This is a blog about process control in chemical , petrochemical and refining industries.Process Controlhttp://www.blogger.com/profile/14994526429003906828noreply@blogger.comBlogger31100tag:blogger.com,1999:blog-7650749522145856099.post-74042618486751896212009-08-18T02:37:00.001-07:002009-08-18T02:37:36.286-07:00<span xmlns=''><p>The most important part in tuning PID controller is to know your control objective. <br /></p><p>Ask yourself the following question to define your control objective <br /></p><p> </p></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/7650749522145856099-7404261848675189621?l=practicalprocesscontrol.blogspot.com' alt='' /></div>Process Controlhttp://www.blogger.com/profile/14994526429003906828noreply@blogger.com0tag:blogger.com,1999:blog-7650749522145856099.post-67263384723471462932009-08-14T07:04:00.001-07:002009-08-14T07:04:00.881-07:00<span xmlns=''><p>Much has been said and written about the PID tuning.<br /></p><p>Some people argue that tuning is best done manually and can never be done by computer programs.<br /></p><p><br /> </p><p>For the beginners, in process control , one of the basic questions will be "can PID loops be really tuned by softwares?" ( well, atleast , I had this question in my mind, during my initial years)<br /></p><p>Is it true ?<br /></p><p>Well it is both true and false .<br /></p><p>True in the sense, for a given control objective , it is possible to "calculate" the tuning constants for the specific PID algorithms by computer programs<br /></p><p>And False in the sense, it is the user who has to decide the control objective , because the software can not.<br /></p><p>What is meant by control objectives ?<br /></p><p>Well we know , that a loop can be tuned "slowely" to get a smooth response or tuned aggressively to quickly reject the disturbances. So there exists a trade off between the "robustness" and "aggressiveness" . <br /></p><p>So this "degree of robustness or aggressiveness" must be measureable by some parameter , like "Closed loop time constant " or "Integrated absolute error" or % overshoot etc. If we know this , then we can calculate the tuning constants.<br /></p><p><br /> </p><p><br /> </p><p><br /> </p></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/7650749522145856099-6726338472347146293?l=practicalprocesscontrol.blogspot.com' alt='' /></div>Process Controlhttp://www.blogger.com/profile/14994526429003906828noreply@blogger.com0tag:blogger.com,1999:blog-7650749522145856099.post-64720792269537200682009-08-14T06:40:00.001-07:002009-08-14T18:25:52.755-07:00<span xmlns=""><p>Hello readers,<br /></p><p>Welcome to my blog,<br /></p><p>This is a blog about process control in chemical , petrochemical and refining industries.<br /></p><p>I hope, this blog will be useful , for the beginners and intermediates in this field.</p><p>Please leave your comments.</p><p>Thank you</p></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/7650749522145856099-6472079226953720068?l=practicalprocesscontrol.blogspot.com' alt='' /></div>Process Controlhttp://www.blogger.com/profile/14994526429003906828noreply@blogger.com0