I wrote a small PID lib in C for my projects. It is based on Simulink's (MATLAB) discrete PID and have the following features: P, I and D gains, low-pass filter on derivative action (coefficient: N), upper and lower saturations, sampling time setting and resets for both the integrator and the derivative filter. Comments are in French, if you have troubles understanding the code let me know, I will translate them or explain further. You can find the transfer function of the regulator in the header file. It uses Backward Euler as an integrating method.

If you want to recode it as an exercise, start from that TF PID.h.

Reno kango panelj priborov oboznachenya. Dec 05, 2017  How to setup an PID library on an arduino link to code: https://create.arduino.cc/editor/LogMaker3c-8dff-48cd-93be-e8ed52c5a898/preview. Code with the Arduino. At the beginning of program, it will receive commands from the computer (start/stop motor; motor speed settings; kP, kI, kD gain of PID). Next is void detect_a(): which is an encoder for sum calculation used for speed calculation in the Timer interrupt routine.