11/5/2015 10:56 PM | |
Joined: 9/27/2006 Last visit: 9/26/2024 Posts: 12283 Rating: (2685) |
Hello mbt; PID tuning is the art (it really is more an art than science) of selecting the values for the loop parameters that will stabilize a closed-loop system as fast as possible in case of setpoint change or disturbance, with as little overshoot or oscillations as possible. There have been quite a number of studies done in the past century on loop tuning, leading to various calculation techniques. Look up Ziegler-Nichols, Cohen-Coon, IMC tuning or other loop tuning strategies on the web, for starters. Each one is well-adapted to a specific type of process: Ziegler-Nichols works well generally with a self-integrating process, but shows tendancy to oscillations in a process.showing time-delay. IMC tuning seems to respond well to setpoint changes but poorly in the presence of disturbances. So you need to study different tuning options a bit, and understand your process loop before you start applying different tuning techniques. I can suggest these 2 sites, for starters: This one examines the methods and application of the Ziegler-Nichols and Cohen-Coon techniques, using graphical analysis (easier to use for a beginner) for processes that show no or little time-delay. https://controls.engin.umich.edu/wiki/index.php/PIDTuningClassical This one (and I recommend it heartily) examines techniques for stabilizing processes that are non-integrating or show large time-delays; it uses Laplace transforms, Z-transforms and mathematical analysis, so it requires a bit more study, but it is a good tutorial, with example loops: http://controlguru.com/table-of-contents/ Of course, you could use an auto-tuning software (Siemens has one for its PID controllers), see the following discussion, particularly the replies by Hamid Hosseini: https://support.industry.siemens.com/tf/ww/en/posts/108924/ Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 11/5/2015 10:57:42 PMLast edited by: dchartier at: 11/10/2015 4:08:56 PM |
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12/13/2016 3:07 PM | |
Joined: 9/3/2014 Last visit: 3/13/2019 Posts: 4767 Rating: (123) |
New question published by mohammed.abdelmaksoud is split to a separate thread with the subject How to build a PID controller from scratch step-by-step. Best regards |
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