Howdy DPRG, As per our discussion at RBNO Tuesday evening on PID tuning, check out: https://en.wikipedia.org/wiki/PID_controller and particularly the cool animation of adjusting P,I,D values in the "Manual tuning" section about half way down. There's also a useful "for dummies" page at: https://www.csimn.com/CSI_pages/PIDforDummies.html cheers dpa