We have explored disturbance rejection in the gravity drained tanks process using P-Only and then PI control. In the PI study, we confirmed the observations we had made in the PI control of the heat exchanger investigation. In particular, we learned that PI controllers: ▪ can eliminate the offset associated with P-Only control, ▪ have […]
At the start of a recent Practical Process Control workshop, I asked the attendees what the “D” in PID stood for. One fellow immediately shouted from the back of the room, “Disaster?” Another piped in, “How about Danger?” When the laughter died down, another emphatically stated, “D is for Do not use.” This one got […]
In recent articles, we investigated P-Only control and then PI control of a heat exchanger. Here we explore the benefits and challenges of derivative action with a PID control study of this process. Our focus is on basic design, implementation and performance issues.
The design and tuning of a three mode PID controller follows the proven recipe we have used with success for P-Only control (e.g., here and here) and PI Control (e.g., here,here and here). The decisions and procedures we established for steps 1-3 of the design and tuning recipe in these previous studies remain unchanged as […]
Like the PI controller, the Proportional-Integral-Derivative (PID) controller computes a controller output (CO) signal for the final control element every sample time T. The PID controller is a “three mode” controller. That is, its activity and performance is based on the values chosen for three tuning parameters, one each nominally associated with the proportional, integral […]