Final answer:
The term that describes a situation in control systems where the controller output increases with an increase in process variable measurement is 'A) Positive feedback'. Positive feedback amplifies changes in the system, unlike negative feedback, which aims to maintain stability.
Step-by-step explanation:
In control systems, the term that describes the situation where the controller output increases with an increase in the measurement of the process variable (PV) is A) Positive feedback. Positive feedback amplifies or increases the change in the system, leading to a further increase in the output. This is in opposition to negative feedback, where the system response acts to reduce any change or error and brings the system back to its target or setpoint. Examples of positive feedback in biological systems include blood clotting and childbirth, where the response intensifies until an endpoint is reached. In contrast, negative feedback examples include body temperature regulation and blood glucose control, aiming to maintain homeostasis by negating the effect of deviations from a set point.