New generic PID component

As part of the development of my 3D printing setup I have ported the very popular Arduino PID v1.2.1, by Bret Beauregard, controller code into a HAL component.

Why? It is a simple controller with one feature that it very useful for integrating processes, like 3D printer extruders. Proportional on Measurement. This allows for Zero overshoot to be achieved.

The component is available on my GitHub page at PIDcontroller.c

I hope others find this useful as well.

thank you
can you give a quick workaround how to impplement and get it to work on stepper output
mabe a pinout discription

I'll put together some documentation when I have a chance. Below is an example of using Proportion on Measurement in the loop. 100% controller output giving max heating rate then with a nice glide into the set point with no overshoot needed to cancel out the integral term.



Scott

so it is used for a 3D printing mashine in your case

Just curious why this was needed? Why couldn't the regular PID component that comes with Linuxcnc be used? In other words what does your new PID do that the old one can't, or why is it better for your situation?

The standard PID component has only the option to use Proportional on Error in the PID calculation. To avoid heating overshoot on a 3D printer extruder, Proportional on Measurement can achieve this.

From brettbeauregard.com/blog/2017/06/introdu...onal-on-measurement/

"There are processes out there that are known as “Integrating Processes.” These are processes for which the output from the pid controls the rate of change of the input. In industry these comprise a small percentage of all processes, but in the hobby world these guys are everywhere: Sous-vide, linear slide, and 3D printer extruder temperature are all examples of this type of process. "

And it works!

Scott

scotta wrote: "There are processes out there that are known as “Integrating Processes.” These are processes for which the output from the pid controls the rate of change of the input. In industry these comprise a small percentage of all processes, but in the hobby world these guys are everywhere:

I suspect he has a very narrow view of "industry"

A couple of years ago I had the task of controlling oil pressure using a variable displacement pump where my control input was current to a proportional solenoid valve which fed the same oil into a chamber which varied the stroke of the pump. This was still contollavbe by standard PID, albeit that the P I and D terms were variable factors based on current oil pressure, pump speed and oil temperature.

I am not trying to argue that this approach is valueless, I would have to think about it a lot harder than I feel equipped to do right now. But to imagine that the hobby world is bigger than the industrial world seems naive.