Pid control pdf
But if your application could benefit from the dampening effects of the derivative, you will need to find the value that works! There are many PI controllers out there, and for certain applications, this is all that is required.
#PID CONTROL PDF SIMULATOR#
I will post a video at the bottom of this article that shows these steps inside the automated PID Simulator to provide a practical example for those (like myself) who are more visual learners.įor the hands on learners, download the PID Simulator app from the Microsoft Store to put these steps into practice! Derivative Once the controller is stable, and responding desirably… congrats! you now have a working PI controller. If the controller starts to oscillate, or become unstable, adjust the I value in the opposite direction until the controller becomes stable again. The goal of tuning the integral value, is to achieve an adequate controller response or reaction time (after the initial response from the proportional is set). Increase the integral gain in small increments, and with each adjustment, change the set point to see how the controller reacts. Always start with small steps when adjusting a PID controller, and give time between each adjustment to see how the controller reacts. Once the proportional value is found, we can start to tune the integral. This will be the starting P value.Įxample: in the picture, the proportional gain that causes the controller to become unstable is 1000, so the starting proportional value will be 500. Once the proportional value that causes the controller to oscillate is found, take this value and divide it in half. Then increase the proportional until the controller starts to become unstable and oscillate.Ī controller where the oscillations become smaller is considered a “stable” controller, as eventually it will stabilize, and when the oscillations start getting larger is an”unstable” controller. Start by setting the Integral and Derivative values to 0. Once everything is verified, we can start to program! Proportional More times than not, people will try to”tune” PID values to fix an issue, but the issue is a physical one, not an automation one. Finding Initial PID Valuesįirst ensure everything is mechanically sound with the device being controlled. This article will provide solutions to both of these, setting up a PID controller from scratch and more! To start, read “PID Controller Explained“, to learn what a PID controller is and how it works. Tuning a PID controller can be difficult knowing where to start, and what direction to go. Even though many controllers provide auto tune capabilities, an understanding of PID tuning will help in achieving optimal performance. The important thing is not to find the “perfect” values, but to find ones that meet the requirements, and provide desired control. It is good to note early in this post, that there can be many values that work for the same device. And also the PID Simulator page to use a live PID Simulator! To start, read “PID Controller Explained“, to learn what a PID controller is and how it works. This article will provide solutions to both of these, setting up a PID controller from scratch and more!