Self-tuning and adaptation for industrial PID controllers

Three methods for automatic tuning of PID loops are presented. The first one involves identification of step response, preliminary tuning of the controller and one or two corrections of the gain. The second extends standard relay self-tuning to variable gain and phase margin, which depend on delay to time constant ratio. Also an alternative to EXACT adaptive algorithm is presented, where tuning steps are performed along contour lines of three template surfaces. (Self-tuning and adaptation for industrial PID controllers).