Low Cost Process Control Trainers

Process control laboratories in most colleges and universities include process trainers for control exercises in temperature, level, flow, and pressure. Schools are usually limited to a single trainer for each process variable because of system size and cost. The use of single systems makes it difficult to use small laboratory teams without reducing the enrollment limit placed on the laboratory section. Ideally, the process laboratory should have multiple trainers in each of the four process variables to learn the basics of process control. Then the students could move to the larger more robust system to study control of a large industrial process. This paper describes the results of a National Science Foundation (NSF) Instructional Laboratory Instrumentation (ILI) grant that supported the design of a low-cost process control trainer for temperature that introduces students to basic control concepts. Construction cost of the system is less than $500, and all of the components are available off-the-shelf from a number of industrial sources. The systems can be controlled by any single-loop process controller, a programmable logic controller, or a microcomputer using a control software product, such as LabView. In addition, the trainers work well in linear electronics laboratories to teach the use of operational amplifiers in instrumentation systems. The systems have been tested at several colleges and universities with excellent results. This paper describes the system design, construction requirements, example laboratory exercises, and test results. A web site that includes a complete set of drawings for the trainer and other supporting information is available. Send e-mail to James Rehg jar14@psu.edu for the URL.