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6/30/2011 8:00 AM | |
Joined: 6/21/2011 Last visit: 9/18/2024 Posts: 3 Rating: (0) |
Dear Sir, I am using PID FB41(continuous control) for the AGC system. My set point is fixed at 3000 microns and process valve starts from 28000 microns. PID is generating the output to move process variable to 3000 microns but i am facing problem in tuning the PID. when my process value is near to 3000 it fluctuate between -2945 to +3100 microns and process value is not getting almost stable to 3000 microns. I am using only gain and integral time to control the PID output. My scan cycle time is maximum 5 sec and min. 1 sec as i have checked in hardware configuration online. Is there any best possible way to set the gain and integral time for the PID. I have to reduce this fluctuation to plus minus 2 microns. I HAVE ATTACHED THE PHOTO OF PID BLOCK USED PLEASE SUGGEST SOME WAY THANK U
AttachmentNew Folder.zip (157 Downloads) |
6/30/2011 11:55 AM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating: (1365) |
Dear member This would be a good reference: http://www.publicis-books.de/cms/website.php?id=/en/produkte/automatisierungstechnik.htm&action=detail&pid=29479 Please check chapter 8 (calling of software controllers in PLC)and section 9.3.1 for selecting the best cycle for FB41 due to dominant time constant of the process. Also ,Section 9.3 adjustment rules and optimization.There are really useful data in section 9.3.5 which are practical rules of thumbs for SIMATIC S7 controllers. regards |
6/30/2011 2:38 PM | |
Posts: 691 Rating: (37) |
You can use the Dead Band Width for your purpose |
7/10/2011 8:41 AM | |
Joined: 1/28/2009 Last visit: 9/10/2024 Posts: 6849 Rating: (1365) |
Dear chinmaya sendha For more information on tuning issues follow this topic and also check the attached files which is provided by Pegaia. PID tuning Regards AttachmentPID tunning.zip (153 Downloads) |
7/11/2011 2:27 AM | |
Posts: 1 Rating: (0) |
Hello, The call block pid to be done in an ob cyclical, as help is on the block FB41. Regards. |
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