What is an example of feed-forward control?

Feed-forward control is a proactive approach to maintaining system stability and performance, where adjustments are made based on anticipated changes in process conditions rather than relying solely on feedback from the system. In the context of the choices provided, adjusting chemical feed proportional to flow exemplifies feed-forward control because it involves setting the dosage of chemicals in direct relation to the flow rate of water entering the treatment process.

This means that if the flow rate increases, the chemical feed rate is adjusted upward in anticipation of the increased volume of water needing treatment, thereby maintaining the desired water quality without waiting for downstream measurements or feedback that indicate a change in conditions. This anticipatory adjustment helps to prevent issues before they arise, ensuring smoother operations and more efficient use of resources.

In contrast, options such as automatic shut-off for safety, monitoring tank levels, and adjusting pressure based on temperature are examples of feedback control or reactive measures, where actions are taken in response to actual measurements or conditions rather than predictions.