10/6/2010 6:38 PM | |
Joined: 9/27/2006 Last visit: 11/18/2024 Posts: 12296 Rating: (2691) |
Hello tomy; What you are asking sounds very much like a one-size-fits-all tuning of your process, using PID. That is not realistic. We do not know your process, your actuators and sensors, your controllers, the compromises you will need to malke between fast reaction and stability... First, I would suggest yout ake a half-hour to read a few documents on PID parameters, prepared by Ron Beaufort, who has a way of presenting his material without too much reliance on math (which can be a relief, at times). He does make you understand how each parameter affects the process, in its own way: http://www.ronbeaufort.com/sample_lessons.htm Look at the 3"What is P (I, D)in PID" lessons, and study them before you attempt to tune your loop. It is important you understand the proinciples of feedback loop control before you attempt it in a real process. Next, there are various ways to obtain the (approximately) best values for a PID loop, based on test and tweak methods, manual mode test and math methods (such as -Ziegler-Nichols: http://www.mstarlabs.com/control/znrule.html - Cohen-Coon: http://www.chem.mtu.edu/~tbco/cm416/cctune.html -and many others: http://www.google.ca/#hl=en&biw=1259&bih=819&q=pid+tuning+methods&aq=3&aqi=g2g-c1g7&aql=&oq=pid+tuning&gs_rfai=&fp=1d6496f6448fa324). Loop-tuning software is available from many sites, especially well-knowis Expertune but many other providers are promoting their software on the web. Mathematical packages such as Matlab and Scilab also have loop tuning add-ons. A fully mathematical model-based tuning process is described (with examples) on the www.controlguru.com site. Hope this helps, Daniel Chartier |
This contribution was helpful to2 thankful Users |
10/7/2010 7:29 PM | |
Joined: 9/27/2006 Last visit: 11/18/2024 Posts: 12296 Rating: (2691) |
Hello Tomy; This quote is from the S7-200 system manual, chapter 15, on Autotune functions: Prerequisites The loop that you want to auto-tune must be in automatic mode. The loop output must be controlled by the execution of the PID instruction. Auto-tune will fail if the loop is in manual mode. Basically, it seems to me that this requires the PID loop to be already tuned, maybe not perfectly, but withvalid parameter values, before you apply the autotune functions. |
Last edited by: dchartier at: 10/7/2010 7:31 PM |
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10/9/2010 5:40 PM | |
Joined: 5/4/2009 Last visit: 5/28/2024 Posts: 914 Rating: (40) |
OK... I will try my best, and give you feedback accordingly. Regards. Tomy.
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Aim Higher |
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10/10/2010 9:48 PM | |
Posts: 1 Rating: (0) |
thank u |
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