Vance VanDoren, Ph.D., P.E. Control Engineering

Analyzing Closed-Loop Behavior with Convolution

The repeatable behavior of a linear process allows a process controller to predict the future effects of its current efforts. As described in “Process Controllers Predict the Future” (March 2008), a controller’s predictive abilities can be reduced to a mathematical formula by conducting the following experiment: 1) Stimulate the process in open-loop mode by forcing the control...

Advances in Control Loop Optimization

There was a time when “control loop optimization” meant selecting the proportional, integral, and derivative tuning parameters for all of the PID controllers in a plant so as to optimize the closed-loop performance of each loop individually. Loop tuning is still a critical element of loop optimization, but thanks to recent advances in control theory and commercial software products,...

Applications of Self-tuning Control

Loop tuning is as much an art as it is a science. A well tuned feedback control loop can quickly and safely eliminate errors between the process variable and the setpoint, but endowing the controller with the necessary balance of aggression and patience requires a certain degree of skill and experience.

Fundamentals of Self-Tuning Control

Although proportional-integral-derivative controllers or “PID loops” have been the de facto standard of industrial feedback control for more than 65 years, they’re not always easy to use. For PID loops to perform up to their potential, they must first be tuned to fit each application, then periodically re-tuned to maintain the desired closed-loop behavior.