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What is the Process Time Constant? How Do I Calculate the Time Constant of A Process?

By Control Guru | January 13, 2015

Party hosts often cringe when guests arrive early or late. Seemingly subtle shifts in timing can throw off planned details that are of importance to the host and utterly lost on guests. So too the timing of a PID control loop’s response is important. Premature or delayed responses negatively impact the controller’s performance. Previously the calculation of Process Gain – the “how far” variable – was covered. The Process Time Constant is equally important to process modeling and PID controller tuning. As with most things, timing is everything.

How Should Control Loop Performance Issues Be Prioritized?

By Control Guru | January 7, 2015

There are many paths to Heaven or so the saying goes. With a growing array of automation technologies, such a philosophical expression can be applied to process control and plant-wide optimization. Whether the goal is focused on uptime, throughput, or quality, control loop monitoring and diagnostic solutions provide meaningful insight into a facility’s performance. The insights gained from these technologies enable practitioners to proactively address bothersome issues before they become costly problems, and lead somewhere other than Heaven.

How Do I Calculate Gain? What Is the Difference Between Process Gain and Controller Gain?

By Control Guru | December 29, 2014

Among practitioners who tune PID control loops manually most note their focus on calculating the Gain. Process Gain is a model parameter whereas Controller Gain is a tuning parameter. The former describes important aspects of a given process’ dynamic behavior. The later contributes to the PID controller’s responsiveness to disturbances.

What Are the Pros and Cons of the Step Test?

By Control Guru | December 23, 2014

Face it, more often than not tuning a PID controller is usually easier when software is applied. While not all products are created equal, the modeling capabilities within most commercial controller tuning software products can account for dynamics that are often overlooked by the human eye. Noisy and oscillatory data can thwart even the most experienced among us. So what should a practitioner do when the use of tuning software isn’t an option? The answer: Perform a step test.