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.
