基于PLC自来水厂自动控制系统毕业设计.doc

编号

本科生毕业设计

基于PLC自来水厂自动控制系统设计

The Subject of Graduation Project

学生姓名

专业

学号

指导教师

分院

2017年3月

摘要

供水是一个关系国计民生的重要产业，随着我国改善人民生活条件、建设小康社会及提高劳动生产水平等目标的实现，对自来水水质的要求也越来越高。水处理厂计算机自动化控制系统是保证安全、连续、优质供水的措施。本文通过分析国内外已建水厂自动化控制系统的现状，结合工艺设备智能化的发展趋势，以及我国中小型水厂现状，设计了一套以PLC S7-200作为控制器的自来水自动控制系统，该系统能实时监测水质、取水流量、pH值、管网压力，监控厂区安全，自动控制投矾、加氯，还能自动存储历史数据。此系统不仅能降低能耗、节约成本、减少维修维护工作强度、提高管理水平、确保供水质量，还能推进我国给水工艺的发展，对减小与先进水平的差距都具有现实意义。通过运行情况表明，该系统功能齐全，性能稳定可靠，具有较强的实用性和推广价值。

关键词：PLC 自动化控制系统上位机监控系统

ABSTRACT

The water service is a significant industry in national welfare and the people's livelihood. With the quickening pace of people's living standard and the objective of achieving building a well-off society and enhancing productivity level, the water supply is increasingly demanded for the high quality. The computer automation control system of the waterworks is an effective measure for guaranteeing the high quality of the water supply in security and continuity. This article, which combines with the development tendency of the processing equipment intelligent and the reality of small and medium-sized water treatment plant in our country, has designed a water supply automatic control system of PLC S7-200 controller by analyzing the reality of the waterworks automation control system both at home and abroad. This water supply automatic control system can in real time monitor the water quality, the water draw rate, the pH value, the pipe network pressure, the monitor site area security, etc. Besides, the system can automatically add vitriol and throw chlorine; also, the system can auto save historical data. In addition, the system, in which there is an operation significance for reducing the gap with advanced standards, not only cuts down the energy consumption, saves cost, reduces the service maintenance working strength, enhances the management level, guarantees the water supply quality, but also improves the advancement of the water supply technology. The running conditions of the system reveal that its system function is complete; its performance is stable and reliable; there are strong practicability and promotion value.

Key word：PLC automatic control system position machine of monitor and control system

目录

第一章引言 (1)

1.1 本课题的研究背景和意义 (1)

1.2 国内外水厂自动控制的现状 (1)

1.3 本课题的主要研究的内容 (2)

1.4 系统及仪器仪表说明 (3)

第二章 PLC的概况及结构图 (6)

2.1 PLC的简介 (6)

2.2 PLC的工作原理 (6)

2.2.1自诊断测试扫描过程 (6)

2.2.2与网络进行通信的扫描过程 (6)

2.2.3用户程序扫描过程 (6)

2.2.4读输入、写输出扫描过程 (6)

2.3 PLC的结构图及其各部分的功能 (6)

2.3.1中央处理单元（简称CPU） (7)

2.3.2存储器 (7)

2.3.3输入单元 (7)

2.3.4输出单元 (7)

2.3.5电源 (7)

第三章 PLC控制系统设计 (8)

3.1 PLC程序设计的步骤 (8)

3.1.1程序设计前的准备工作 (8)

3.1.2程序框图设计 (8)

3.1.3编写程序 (8)

3.1.4程序调试 (9)

3.2 S7-200 PLC选型 (9)

3.3 控制过程设计 (9)

3.3.1 PLC控制自动加矾 (9)

3.3.2 PLC控制自动加氯 (10)

3.3.3 工控机单元 (10)

3.4 PLC编程 (10)

3.4.1 PLC控制系统工作流程 (10)

3.4.2西门子S7-200型PLC控制I/O分配表及中间变量分配表 (11)

3.4.3 西门子S7-200型PLC控制梯形图 (11)

3.5 程序调试 (16)

第四章总结与展望 (20)

致谢 (21)

参考文献 (22)