【作者】 倪水；

【导师】 徐刚；

【作者基本信息】 江苏大学 ， 机械电子工程， 2003， 硕士

【摘要】 在工业生产过程中，经常需要对固体和液体的物位进行准确测量，从而实现对企业生产过程的自动化检测和智能控制，以提高企业生产效率，实现生产过程的无人化管理。 由于本研究系统被测对象环境温度较高且潮湿，同时料仓中有大量粉尘及蒸汽，因此传统的料位检测方法不能满足本测试要求。本文在分析国内外各种物位检测技术的基础上，针对特殊工况下动态物料高度的检测进行了系统的探讨与研究。首先建立了料仓中的压力分布数学模型，推导出料位高度与仓底均布压力间的数学关系式，并据此设计了中温电阻应变式压力传感器，同时对它在实际应用中存在的零点漂移等问题提出了改进措施，提高了传感器性能，解决了上述特殊工况下动态物料检测的技术难题。同时为适应工厂要求对多目标、多参数进行监测的要求，采用了分布式计算机控制系统，该系统以AT89C52单片机为核心，内部集成了信号调理、数据采集与处理、显示等电路并扩展了大容量存储器以保存最近几次生产过程的检测数据，同时还采用了RS485网络总线技术可以方便的将数据传输给上位控制中心。为了实现生产过程的自动化控制，在总结人工手动操作经验基础上，单片机控制系统中采用了模糊控制算法，可以根据实时采集到的高度值输出相应的电压控制量来调节输料管阀门的开度大小，从而实现对料位高度的智能控制。程序设计采用模块化设计思想，分别用C51语言编写单片机代码和Borland C++语言设计上位机程序来实现控制系统所要求的功能，并对串口类的实现、多线程的创建等几个关键问题作了介绍。更多还原

【Abstract】 In the industrial procedure,solid or liquid level should often be measured accurately to implement the automatic monitoring and unwatched management of enterprise production.The traditional level measuring methods cann’t meet our demand because the subjective investigated is in such a poor systemic condition that the temperature is a little high and there’s so many mill dust and steam there.In this article we perform systemic discuss and research against the dynamic level measuring method under special working condition on the basis of analyzing kinds of level measuring technique in and abroad.First we establish the pressure distribution mathematic model in storage bin and then deduce the mathematic relation between level height and the uniform stress on the bottom of the bin and designed a resistance compressive stress sensor used for the special condition and put forward a resoivement according to its zero excursion existing in practical use. In order to reach the requirement of applying for the multi-objective and multi-parameter measuring,we adopt the distributing computer controlling system which the AT89C52 single chip was used as core in the system,also the circuit of signal conditioning and data acquisition and processing are all integrated in the system. We use nixie tube to fullfill the displaying function and adopt high-capacity memory to record the data of production process. In order to transmit the data collected to the upper control center,the RS485 network bus technique has been employed in the monitoring system to complete the function of communication between the microcontrollers and upper PC computer.In order to implement the automation of production process,we use fuzzy control algorithm routine in the single chip.lt can adjust the opening angle of electric valves with corresponding voltage according to the real-time material level that measured and so the automation control of material level was implemented. In design of programming,we use modularization design method and adopted the actual prevalent Keil C51 compiler to write the code of single chip controller. As regards of upper PC computer,we adopted Borland C++ language to design the program interface and implement the function of control system,what’s more several key component such as the implementation of serial port class and the creation of multi-thread were also introduced here.更多还原