Use of an Air Process Control Trainer to Teach PID Control

Abstract

In the Mechanical Engineering Technology (MET) program at Indiana University - Purdue University Indianapolis (IUPUI), all bachelor degree students are required to take a course in Instrumentation. This course includes material on measuring and controlling mechanical parameters such as temperature, pressure and flow. Students are taught the basis of feedback control systems, primarily proportional-integral-derivative (PID) control. The MET approach is physical, rather than the mathematical approach favored by electrical engineering technology. Such a pedagogical method relies on laboratory equipment and experiments whereby the features of PID control may be properly demonstrated. As an example, the student observes how different PID settings affect the fan speed in the control of air flow through a duct. Through the support of an ILI grant from the National Science Foundation, the MET program was able to purchase six Air Process Control Trainers to be used with personal computers supplied by the MET department. These units are used to control air speed and temperature in forced air flow through an instrumented duct. This paper will describe the equipment, the experimental procedure utilized, and the results, with a summary of the benefits to the students.