The Fuzzy-PI Control Of Room Temperature Based On PLC

As the modern technology progresses at great speed, the pharmacy of biology develops rapidly accordingly. In order to meet the demands of the market, people have to make the plans in real time, flexible, and at the same time, having no affection on the productivity. PLC (Programmable Logic Controller) is applied widely in the field of control industry owing to its high dependability, free programming and flexible configuration. Because of the complexity and much disturbance of air conditioners system, in order to assure medicine quality, it is significant to adopt the control system, which can meet the requirement of temperature, humidity, and good adaptability.This thesis introduces the theory of fuzzy control in the course of temperature controlling; and adopts the means of modulating the parameters of Proportional-Integral-Controller according to dynamic features of the system. At first, the author thoroughly analyzes the characteristics of constant temperature room and builds the math model of the temperature control system. Then, based on these, the author establishes the math model of practical project by some simplification on the basis of actual situations, hi the end, by making use of the arithmetic of Fuzzy- Proportional-Integral, the author cultivates the Fuzzy-Proportional-Integral-Controller on PLC, and adopts it to practice. The simulation of MATLAB proves the correctness of model. The results of the application show the superiority of adopting Fuzzy- PI- Controller over conventional Pi-Controller in the aspects of reducing excess adjustment, abbreviating adjusting time and having good adaptability.