PLC恒压供水控制系统毕业论文

广东轻工职业技术学院

（继续教育学院）

机电工程系

毕业设计（论文）

题 目： P L C 恒 压 供 水 控 制 系 统

专 业： 电 气 自 动 化

设计指导老师： 颜 学 定

毕业设计学生： 黄 志 孝

学 号： 10833076200101189

毕业设计日期：2009年11月9日~2009年12月22日

P L C恒压供水控制系统设计

目录

目录 .................................................................................................................................................. 1 摘要 .................................................................................................................................................. 3 Abstract ....................................................................................................................................... 4 1.设计任务书 ................................................................................................................................... 5

1.1设计题目： ......................................................................................................................... 5 1.2设计目的 ............................................................................................................................. 5 1.3设计内容及要求 ................................................................................................................. 5 1.4设计进程安排 ..................................................................................................................... 6 2.PLC恒压供水控制系统 ................................................................................................................ 7

2.1引言 ..................................................................................................................................... 7 2.2恒压供水PLC控制系统的基本策略 ................................................................................. 7 2.3恒压供水系统的基本构成 ................................................................................................. 7 2.4 工作原理 ............................................................................................................................ 8 3.PLC的概述 .................................................................................................................................. 10

3.1PLC的组成 ......................................................................................................................... 10 3.1.1PLC的输入 ..................................................................................................................... 10 3.1.2 PLC的输出 ................................................................................................................. 10 3.1.3 PLC的控制机制 ......................................................................................................... 10 3.1.4 PLC的定义 ................................................................................................................... 13 3.1.5 PLC的特点 ................................................................................................................... 13 3.1.6 PLC的性能指标 ........................................................................................................... 14 3.1.7 PLC的分类 ................................................................................................................. 14 3.2 PLC工作原理 ................................................................................................................... 15 3.2.1 循环扫描 .................................................................................................................... 15 3.2.2 I/O响应时间 ............................................................................................................. 17 3.2.3 PLC中的存储器 ......................................................................................................... 17 3.3 PLC的编程语言 ........................................................................................................... 18 3.3.1 PLC的编程结构功能图 ............................................................................................. 18 3.3.2 梯形图编程语言 ........................................................................................................ 19 3.4 PLC的分类 ....................................................................................................................... 21 3.4.1 按I/O点数容量分类 ................................................................................................ 21 3.4.2 按结构形式分 ............................................................................................................ 22 3.5 PLC与继电器控制系统的区别 ..................................................................................... 23 3.6 PLC控制系统的结构 ..................................................................................................... 24 3.6.1 单机控制系统 .............................................................................................................. 24 3.6.2 集中控制系统 ............................................................................................................ 25 3.6.3 分散控制系统 ............................................................................................................ 26 3.7 PLC网络及特点 ............................................................................................................... 27 2.7.1 网络概述 .................................................................................................................... 27 3.7.3 网络控制系统PLC的影响 ........................................................................................ 27 3.7.4 网络控制系统的设计 ................................................................................................ 28

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P L C恒压供水控制系统设计

3.7.5 访问控制技术 ............................................................................................................ 28 4 .系统硬件设计 ........................................................................................................................... 29

4.1 系统控制要求 ................................................................................................................ 32 4.2 系统选型 ........................................................................................................................ 32 4.3 PLC模拟量控制单元的配置以及应用 ......................................................................... 34 4.3.1 EM235模拟量工作单元性能指标 ............................................................................. 34 4.3.2 校准及配置 ................................................................................................................ 36 4.3.3 EM235的安装使用 ..................................................................................................... 36 4.3.4 EM235工作程序编制 ................................................................................................. 36 5.水泵电机的选择 ......................................................................................................................... 39

5.1.概述 .................................................................................................................................. 39 6.SMART-1151压力变送器 ............................................................................................................ 40

6.1.1151型变送器 ................................................................................................................. 40 6.2.工作原理 .......................................................................................................................... 40 6.3.管网压力 .......................................................................................................................... 41 设计总结......................................................................................................................................... 43 致谢 ................................................................................................................................................ 44 参考文献......................................................................................................................................... 45

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P L C恒压供水控制系统设计

摘要

利用自动控制程序PLC恒压控制三台水泵电机供水给生活小区生活用水。采用可编程控制器（PLC）构成控制系统进行优化控制泵组的运行，并自动调整泵组的运行台数，完成供水压力的要求，在管网流量变化时达到稳定供水压力和节约电能的目的。系统的控制目标是泵站总管的出水压力，系统设定的给水压力值与反馈的总管压力实际值进行比较，其差值输入CPU运算处理后，发出控制指令，控制泵电动机的投运台数工作而达到给水总管压力稳定在设定的压力值上。供水系统选用原则水泵扬程应大于实际供水高度，水泵流量总和应大于实际最大供水量。

关键词：PLC，自动控制系统，控制指令

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Abstract

Constant Pressure Control Automation PLC program using three water pump motor water to the living quarters for domestic use. A programmable controller (PLC) constitute a control system to optimize control of the operation of pumping systems and pumping systems automatically adjust the number of operating units to complete the requirements of the water supply pressure in the pipe network to stabilize the water flow changes the pressure and energy conservation purposes. System control objective is to pump the water mains pressure water supply system set pressure value of the mains pressure and feedback to compare the actual values, the difference between the input CPU computing processing, issuing control instructions to control the pump motor is put into operation in the number of work units to achieve the water supply mains pressure to stabilize at the set pressure value. Water supply systems use the principle of pump head should be larger than the actual water height, water pump flow rate should be larger than the sum of the maximum actual water supply. Key words: PLC, Automatic control system, Control instructions.

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