A 'Proportional Only' controlled automatic process loop is oscillating continually, above and below the set point. To stabilize this controller and loop using the 'gain' adjustment, what controller/loop response would you expect upon process changes vs. set point?

Correct Answer: Option C — By decreasing gain gradually, the process should stabilize in a 'quarter wave' response to system's upsets vs. the set point.

In a proportional control loop, excessive gain causes instability and continuous oscillation. Decreasing the gain reduces the controller's sensitivity to process errors, allowing the system to dampen oscillations and achieve a stable 'quarter wave' decay response, where each successive oscillation is significantly smaller than the previous one.