Like the P-Only controller, the Proportional-Integral (PI) algorithm computes and transmits a controller output (CO) signal every sample time, T, to the final control element (e.g., valve, variable speed pump). The computed CO from the PI algorithm is influenced by the controller tuning parameters and the controller error, e(t). PI controllers have two tuning parameters […]

In modern plants, process variable (PV) measurement signals are typically scaled to engineering units before they are displayed on the control room HMI computer screen or archived for storage by a process data historian. This is done for good reasons. When operations staff walk through the plant, the assorted field gauges display the local measurements in […]

In a previous article, we looked at the structure of the P-Only algorithm and we considered some design issues associated with implementation. We also studied the set point tracking (or servo) performance of this simple controller for the heat exchangerprocess. Here we investigate the capabilities of the P-Only controller for liquid level control of the […]

We have discussed the general proportional only (P-Only) algorithm structure and considered important design and tuning issues associated with implementation. Here we investigate the capabilities of the P-Only controller on our heat exchanger process and highlight some key features and weaknesses of this simple algorithm. The heat exchanger process used in this study is shown […]