本科生毕业设计说明书（毕业论文）
毕业设计说明书（毕业论文）
工业污水处理自动控制系统
摘 要
近年来,污水处理厂已成为各个城市最重要的基础设施之一。尤其是中小城市,新建或扩建污水处理厂已成为当地政府改善人民生活水平的头等大事。随着自动化技术、计算机技术的不断发展、完善,污水处理厂的自动化水平也相应提高。而PLC控制器以其技术成熟、通用性好、可靠性高、安装灵活、扩展方便、性能价格比高等一系列优点，在工业控制中得到了越来越广泛的应用。本文主要介绍了污水处理厂自动控制系统的组成、功能及如何利用PLC实现自动控制,并介绍了在系统实施中遇到的若干问题及其解决措施。在污水处理中采用PLC控制系统改造后，提高了自动控制的可靠性,不仅减轻了工人的劳动强度,而且提高了污水处理厂的运行效率和运行效益,实现了污水厂生产管理的科学性。
关键词：PLC；污水处理；硬件
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毕业设计说明书（毕业论文）
Industrial wastewater treatment automatic control system
Abstract
In recent years, sewage treatment plant has already become one of the most important infrastructures in every city, and especially in small and medium-sized ones, to build and expand such plants has been on the local governments’ top agenda to improve peoples’ life. With the development and improvement of automation technique and computer technology, automation level of sewage treatment plants has also made a corresponding leap. While PLC has series of merits such as: mature technique, fine universal property, high reliability, flexible to install, convenient to expand, excellent cost performance, etc, which have enabled it gain a more and more widespread application in industrial control. This paper will mainly introduce the composition and function of the automatic control system in sewage treatment plants and several problems that may occur in the practical use of the system and the possible solutions to them. Since the transformation by employing PLC control system in sewage treatment, the reliability of automatic control has been advanced, which has not only reduced workers’ work intensity, but also improved the operational efficiency of the sewage treatment plants, thus has made the scientific administration of manufacturing in sewage treatment plants possible.
Key words: PLC;Sewage treatment;Hadware
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毕业设计（论文）
目录
摘 要............................................................................................................................ I ABSTRACT .................................................................................................................. II 第一章绪论.................................................................................................................... 5 1.1工业污水处理的国内外现状 ............................................................................. 6 1.2课题的背景 ......................................................................................................... 6 1.3研究目的和意义 ................................................................................................. 7 第二章 工业污水处理控制系统工艺流程的介绍...................................................... 9 2.1工业污水处理基本概念 ..................................................................................... 9 2.2常用的工业污水处理工艺 ............................................................................... 10 2.3本设计系统工业污水处理工艺及描述： ....................................................... 12 2.4工业污水处理系统控制形式 ........................................................................... 13 2.5工业污水处理系统的功能要求 ....................................................................... 14 2.5.1信号输入 .................................................................................................... 15 2.5.2控制输出信号 ............................................................................................ 15 第三章 硬件设备配置................................................................................................ 16 3.1主要组成部分 ................................................................................................... 16 3.2电气控制系统 ................................................................................................... 17 3.3工业污水处理自动控制系统的工作原理 ....................................................... 18 3.3.1控制系统总体框图 .................................................................................... 18 3.3.2工作过程 .................................................................................................... 18 3.3.3工业污水处理系统主电路设计 ................................................................ 19 3.4 PLC的应用 ......................................................................................................... 19 3.4.1 PLC简介 ................................................................................................... 19 3.4.2 PLC选型 ...................................................................................................... 22 3.4.3 PLC的I/O资源配置 .................................................................................. 23 3.5其他硬件的选型 ............................................................................................... 25
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毕业设计（论文）
3.5.1电动机的选型 ............................................................................................ 25 3.5.2.接触器的选型 ............................................................................................ 27 3.5.3时间继电器选用 ........................................................................................ 28 3.5.4变频器的应用 ............................................................................................ 28 3.5.5液位差计 .................................................................................................... 32 3.5.6软启动器的应用 ........................................................................................ 33 第4章 软件系统设计.............................................................................................. 38 4.1总体流程设计 ................................................................................................... 38 4.1.1手动模式 .................................................................................................... 38 4.1.2自动模式 .................................................................................................... 39 4.2曝气过程控制的任务 ....................................................................................... 45 4.3氯气投加环节 ................................................................................................... 46 4.4絮凝剂投加环 ................................................................................................... 46 4.5 PID控制 ............................................................................................................. 47 4.6 PLC和变频器，软启动器通讯 ......................................................................... 48 第5章 调试和运行结果.......................................................................................... 49 5.1硬件系统的调试 ............................................................................................... 50 5.2软件系统的调试 ............................................................................................... 50 5.3运行结果 ........................................................................................................... 51 结论.............................................................................................................................. 53 参考文献...................................................................................................................... 54 致谢.............................................................................................................................. 55
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