摘要我这次所设计的恒温箱具有温度自动调整的功能。首先我对恒温箱做了个概述，包括对恒温箱进行研究的目的和意义，恒温箱的国内外研究现状等。接着对恒温箱提出了设计内容和要求，说明我要设计的恒温箱是基于Smith算法的恒温箱，与其他恒温箱相比，我设计的恒温箱有自动调节温度的功能，可靠性比较高，它所测量的温度也很精确。然后我展开了对恒温箱控制系统的讨论。先作出恒温箱系统的框图，确定总体的设计方案；再阐述Smith算法的补偿原理并且对其进行仿真，借此用来验证选择Smith算法的正确性。由于我设计的系统的电路中包含了晶闸管，因此过零检测也是一个必要的环节。我之后对过零检测也进行了论述，显现出它的必要性。接下来我又对硬件进行了设计，从单片机的选取开始，我选择了AT89C2051，对于温度传感器、键盘和显示电路，我都有进行适当的选取。在驱动电路中，我选取电阻丝作为加热器，用风扇冷却的方法对恒温箱内部进行冷却。紧接着我就对系统的进行了软件设计，绘制了软件流程图。最后对整个系统进行调试，我通过加温和降温的模拟试验，确保我设计的系统是可行的。76791

毕业论文关键词：Smith算法  恒温箱  单片机  温度控制

Design of Constant Temperature Box Based on Smith Algorithm

Abstract   The constant temperature box I designed has the function of automatic temperature adjustment。 First, I made an overview of the thermostat, including the purpose and significance of the research of the thermostat,   the present situation of constant temperature box at home and foreign countries etc。。 Then on the constant temperature box proposed design contents and requirements, that I want to design thermostat thermostatic container based on Smith's algorithm, compared with other constant temperature box, I design the constant temperature box with function of automatic adjustment of temperature, high reliability, it measured the temperature precise。 Then I started the discussion about the control system of the constant temperature box。 First to make the block diagram of the thermostat system, determine the overall design scheme; and then explain the compensation principle of the Smith algorithm and its simulation, which is used to verify the correctness of the choice of Smith algorithm。 Because of the circuit of the system that I design contains the thyristor, the zero crossing detection is also a necessary part。 After I have also discussed the it, showing its necessity。 Then I design the hardware, starting from the selection of single chip machine, I chose the AT89C2051, for the temperature sensor、keyboard and display circuit, I have the suitable selection。 In the drive circuit, I select the resistance wire as the heater, the cooling method of the fan is used to cool the inside of the constant temperature box。 Then I have a software design of the system, drawing the software flow chart。 Finally, debugging the whole system, I through the heating and cooling of the simulation test, to ensure that I designed the system is feasible。

Key words: Smith algorithm  constant temperature box  single chip machine  temperature control

目  录

摘   要 I

Abstract II

目  录 III

图清单 V

表清单 V

1 概述 1

1。1 恒温箱控制系统的概述 1

1。2 研究课题的目的及意义 2