【作者】 林垂涛；

【导师】 郭文川；

【作者基本信息】 西北农林科技大学 ， 农业电气化与自动化， 2009， 硕士

【摘要】 为了研究昆虫热特性,本文以单片机、可控硅及DS18B20数字温度传感器为核心,运用单片机开发方法、程序设计方法和系统仿真调试方法设计了一个昆虫加热板温度测控系统。根据系统要求,设计了系统基本结构,确定系统总体方案;根据加热板工作过程,设计了加热板控制方案,以可控硅过零方式调节加热板加热功率,以PID控制算法计算控制量。分析系统主要功能,设计了系统硬件电路,编写系统软件程序。以AT89C51单片机为控制核心,运用Keil C51开发平台、采用C语言设计了单片机程序对加热板温度进行采集、处理和传输。温度采集电路以1-Wire总线型数字温度传感器DS18B20作为温度采集单元,分四路采集加热板温度,输出数字信号给单片机以供处理。采用PID控制规律和可控硅过零触发方式调节加热板加热功率,设计了过零脉冲产生电路和可控硅触发电路。在单片机与计算机通信过程中,由于单片机的串行接口输出的是TTL电平,本文采用MAX232芯片设计了通用的RS232电平转换电路对其进行电平转换,计算机与单片机之间采用串行通信异步传输。在上位计算机操作界面部分,利用VB6.0集成开发环境制作了人机交互界面。在加热过程中,人机界面能实时显示昆虫的温度并能绘制出温度随时间变化的曲线,还能根据需要设置系统参数,包括加热速率、通信端口等;界面操作简单、方便。运用Proteus ISIS仿真软件对设计的系统进行仿真调试,在仿真调试过程中弥补系统的不足之处并逐步完善系统,最终完成系统设计。该系统具有良好的人机交互界面,能够准确记录各种昆虫特别是一些害虫在加热过程中的温度变化过程。所测得的昆虫温度变化过程的一些数据将会给昆虫的检疫以及射频热处理杀虫技术提供有价值的参考。更多还原

【Abstract】 In order to study the thermal characteristics of insects, SCM, SCR and digital temperature sensor DS18B20 were used as the major parts in designing a set of heating block temperature measuring and control system.On the basis of system requirements, the basic structure of the system is designed and the system overall plan is determined. According to the working process of heating block, the controlling scenario of heating block is designed. It used triac Zero-crossing way to adjust the heating block heating power and used PID control algorithm to calculate the control volume. Analyzing the main functions of the system, the hardware circuit is designed and the procedures of system software are written. Using AT89C51 as the control core, using Keil C51 development platform and C language to design SCM program to collect, process and transmit the temperature of the heating block. 1-Wire bus digital temperature sensor DS18B20 is used as the temperature acquisition unit to design temperature acquisition circuit. It divided four groups to collect the temperature of heating block and output digital signal to the SCM for processing. Using PID control law and triac zero-crossing trigger way to adjust heating power of heating block, zero-crossing pulse generator circuit and thyristor trigger circuit is designed. Because SCM output TTL electricity, we need to design the conversion circuit in the communication course of SCM and computer. In the communication of SCM and computer, because SCM serial interface output is TTL level, this paper used MAX232 chip to design common RS232 level conversion circuit for its conversion. It used asynchronous transmission of serial communication between SCM and computer. In the upper part of the computer interface, a man-machine interface is produced, using VB6.0 integrated development environment. In the heating process, the human-machine interface can display the temperature of insects and can draw up the curve about temperature along with the time variation. It can also according to need to set the system parameters, including heating rate, communication port and so on. Interface is simple and convenient.The system which has been designed is simulated and debugged using the simulation software Poteus ISIS. Then it can make up for the inadequacies of the system , gradually improve the system, and finished the system at last. This system has a good man-machine interface. It can record temperature history of insect pests which were heated. The data about temperature history of insect pests offers valuable reference insects quarantine and RF insecticidal treatment technology.更多还原