论文总字数：23744字

摘 要

水是生命之源。我国是13个人均水资源最贫乏的国家之一。人均水资源仅占世界人均量的1/4 。到20世纪末,全国600多座城市中，已有400多个城市存在供水不足，其中比较严重的缺水城市达110个，全国城市缺水总量为60亿立方米。但我国工业吨产品的耗水量却是世界平均水平的5～10倍，其中占工业用水量70％的循环冷却水系统是用水的大户。如何有效地提高循环冷却水的浓缩倍数，已成为工业生产的重要关键。

本文简介了课题的研究背景，详述了测量循环水浓度的基本知识和原理。在总结现有方法的优缺点基础上，设计出了用电导率法测循环水浓度测量仪。该测量方法减小了电容效应和极化效应的影响，提高了测量精度，简化了仪表的硬件电路设计。同时本文设计了自适应测温电路，可以适用国内外不同的电极探头；开发了外部存储器，可以存储测量的历史数据，并显示数据曲线趋势，同时仪表还带有回差控制的参数设定，便与在实际项目中的控制和应用。

其次，本文重点介绍了浓缩倍数测量仪的硬件设计和软件设计。硬件设计部分介绍了测量仪的主控制器C8051F021单片机。然后介绍了主要硬件模块的电路设计：包括双极性脉冲激励电路、电导测量电路、自适应温度测量电路、LCD显示、键盘等。温度测量电路具有自适应功能，可以连接不同类型的温度传感器，提高了仪表的兼容性。软件部分包括软件的主要流程和设计思想。

关键词： 循环水 电导率 C8051F021 双极性脉冲电压

ABSTRACT

Water is the source of life. China is one of 13 most water-poor country. World per capita water resources per capita is only 1/4. To the late 20th century more than 600 cities nationwide, there is insufficient water supply problem has more than 400 cities, the more serious of 110 urban water, urban water shortages nationwide total of 60 billion cubic meters. However, the industrial water consumption per ton of product in our country is 5 to 10 times the world average, which accounted for 70% of industrial water cooling water system is big water. How to effectively improve the circulating cooling water of concentration, has become an important key to industrial production.

This paper introduced the research background, the basic knowledge and principle of measuring the electrical conductivity is given in detail. On the basis of summarizing the advantages and disadvantages of existing methods, design the adaptive frequency bipolar pulse voltage measuring conductance method. The method reduces the capacitance effect and the influence of the polarization effect, improve the measurement accuracy, simplify the hardware circuit of instrument design. This paper designs the adaptive temperature measuring circuit at the same time, can be applied at home and abroad different electrode probe; Developed the external storage, can measure the history data of storage, and display the data curve trend, convenient user for data analysis and processing; Instrument at the same time also with return difference control parameter setting, and the control and application in actual project.

Secondly, this paper mainly introduces the conductivity table of hardware design and software design. The hardware design part introduces the main controller of conductivity table C8051F021 microcontroller and sensor probe used in the measurement. Then introduces the main hardware module circuit design: including bipolar pulse excitation circuit, conductance measurement circuit, adaptive temperature measurement circuit, LCD display, keyboard, etc. Temperature measurement circuit with adaptive function, can connect different type of temperature sensor, which is suitable for different electrode sensor at home and abroad, improve the compatibility of instrument. Software part includes the main process and design thought. Data processing part mainly introduces the conductivity and temperature compensation on the basis of the principle of least squares method and the algorithm of data processing.

KEYWORDS: The circulating water；C8051F021；Bipolar pulse voltage; Principle of least square

目 录

摘要 II

ABSTRACT III

第一章 绪论 1

1.1 课题选择背景及意义 1

1.2 国内外的研究概况和发展趋势 1

1.2.1 国外的研究现状和发展趋势 1

1.2.2 国内的研究现状和发展趋势 2

第二章 循环水浓缩倍数测量方法 4

2.1 循环水浓缩倍数的测量 4

2.1.1  Cl^-、Ca² 法  4

2.1.2 电导率法  4

2.1.3 SiO2法 5

2.1.4  K 法 5

2.2 电导和电导率的基本知识概述 6

2.2.1 影响溶液电导率大小的因素 7

2.3 双极性脉冲电压信号测定方法 9

第三章 测量仪的硬件设计 12

3.1 测量仪的整体设计方案 12

3.2 单片机的选型 12

3.3 测量仪测量模块的设计 14

3.3.1 双极性脉冲激励源发生电路 14

3.4 温度测量电路的设计 16

3.4.1 铂电阻 16

3.4.2 电桥放大电路原理 17

3.4.3 测温电路 17

3.5 A/D转换器 18

3.6 人机接口电路 19

3.6.1 按键 19

3.6.2 屏幕显示电路 19

第四章 测量仪的软件设计 20

4.1 编程语言及开发环境简介 20

4.2 系统主程序设计 21

4.3 初始化程序设计 23

4.4 采样信号滤波与处理 24

4.5 电导测量 25

4.6 温度补偿的软件实现 26

4.7 通讯模块 27

第五章 结语 29

参考文献 30

致谢 31

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