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Home‐made PIC 16F877 microcontroller‐based temperature control system for learning automatic control
Author(s) -
Abdullah Mikrajuddin,
Budiman Maman
Publication year - 2011
Publication title -
computer applications in engineering education
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.478
H-Index - 29
eISSN - 1099-0542
pISSN - 1061-3773
DOI - 10.1002/cae.20283
Subject(s) - transient (computer programming) , microcontroller , controller (irrigation) , set point , control theory (sociology) , control system , steady state (chemistry) , proportional control , electronic circuit , pic microcontroller , sensitivity (control systems) , instrumentation (computer programming) , temperature control , transient response , heating system , transient state , point (geometry) , automatic control , computer science , control engineering , engineering , control (management) , mechanical engineering , mathematics , electrical engineering , electronic engineering , chemistry , computer hardware , artificial intelligence , geometry , agronomy , biology , operating system
Abstract A closed‐loop temperature control system, which is composed of a thermal plant and a controller, has been developed to support undergraduate students in learning automatic control delivered in the Special Topics in Instrumentation Physics course. The thermal plant was made from a plastic box covering a lamp and a fan, which heats and drains the air in the plastic box, respectively, as well as a temperature sensor. The controller with a proportional control action was realized by employing the PIC 16F877 microcontroller. The control signal updates pulse‐width modulators (PWMs) in which driver circuits turn on or off the lamp and the fan. A mathematical model of the closed‐loop control system was derived and a theoretical transient response was then obtained. It is found that the experimental transient responses were always much lower than the set point and the steady‐state errors were high for the proportional sensitivity ( K P ) lower than 10. For K P higher than 10, the transient responses tend to approach the set point to cause small steady‐state errors. These characteristics are consistent with the theoretical transient response. Further examination revealed that the closed‐loop system is a higher order system due to the action of the PWMs and the driver circuits. © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 10–17, 2011