| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 96 === Based on the tea making culture in Taiwan and the components of coffee machines, it is tried to develop an automatic device suitable for characteristic tea. This study used some simple components to design the tea maker controllers and focused on the development and testing of controllers. A single chip microprocessor has been applied to the key part of control system along with a voltage type temperature sensor measuring temperature. Then, the Celsius degree data are obtained from output voltage by analog to digital converter of microprocessor. Three important parameters were derived: Kp, Ki, and Kd in PID control by using Ziegler-Nichols rule which are substitution for error mathematical function. 6 heating modes were designed to fit 6 characteristic teas（Green tea, Long Jing Tea, Wun Shan Paochong tea, Tieh Kuan Yin tea, White-tip Oolong tea, Black tea）in main control program. This system shows the immediate temperature by seven-segment display. Liquid Crystal Display and buttons are provided for heating modes. It has been proven that the circuit of this system is precise and control process is stable. Experimental results have shown that the precision of constant temperature is within ±2℃ no matter heating or cooling.
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