The percent of the process variable range that causes a change in controller output is often called what?

The term that describes the percent of the process variable range that results in a change in the controller output is known as the proportional band. This concept is integral to control systems and automation processes, particularly in proportional control strategies.

The proportional band indicates the extent to which the controller reacts to changes in the process variable. A smaller proportional band means that even minor deviations from the setpoint lead to larger adjustments in the controller output, resulting in tight control of the process variable. Conversely, a larger proportional band allows for more significant changes in the process variable before the controller output is adjusted, which can lead to less precise control.

In summary, the proportional band is a key parameter in tuning controllers to achieve the desired responsiveness and stability in process control systems. It directly influences how the system behaves in reaction to changes in the process variable, making it a critical concept for effective control engineering.