164. In a closed-loop process control system, what term is used to describe the undesirable characteristic in which the error of a control system oscillates with constant or increasing amplitude?

Instability describes a control system's failure to settle, resulting in error oscillations with constant or increasing amplitude. Stable systems dampen oscillations; marginally stable systems maintain constant amplitude oscillations; unstable systems exhibit growing oscillations. Saturation, error, and deadband represent different system behaviors and do not account for this oscillatory growth.