The tuning of proportional-integral-derivative (PID) control loops was an important change at HollyFrontier’s Navajo Refinery in Artesia, N.M. Its hands-on, “mandraulic” culture was no longer cutting ...
Self-regulating systems with feedback loops, i.e., the routing back of the output of a system to its input, have existed since antiquity and have since become an integral part of modern technology.