Equivalent Time Constants for Nonoscillatory Second-Order Processes

Equivalent time constants are obtained for nonoscillatory second-order processes. In analogy with first-order processes, the equivalent time constant is defined to be the time at which the monotonic step-response of the second-order process reaches approximately 63.3 percent of its steady-state value. These time constants can be applied to the analysis and design of feedback control systems in which oscillations cannot be tolerated.