基于PLC的恒压供水控制系统设计

1、基于PLC的恒压供水控制系统设计摘 要随着社会经济的迅速发展，人们对供水质量和供水系统可靠性的要求不断提高；再加上目前能源紧缺，利用先进的自动化技术、控制技术以及通讯技术，设计高性能、高节能、能适应不同领域的恒压供水系统成为必然趋势。本论文根据中国城市小区的供水要求，设计了一套基于PLC的变频调速恒压供水系统。由变频器、PLC、PID调节器和组成控制系统，调节水泵的输出流量。电动机泵组由三台水泵并联而成，由变频器或工频电网供电，根据供水系统出口水压和流量来控制变频器电动机泵组的速度和切换，使系统运行在最合理状态，保证按需供水。本文介绍了采用PLC控制的变频调速供水系统，由PLC进行逻辑控制，由

2、变频器进行压力凋节。再经过PID运算，通过PLC控制变频与工频切换，实现闭环自动调节恒压变量供水。运行结果表明，该系统具有压力稳定，结构简单，工作可靠等特点。关键词：变频调速 ；恒压供水；PID调节；PLCWater Supply Control System of Constant Pressure Based on PLC显示对应的拉丁字符的拼音ABSTRACTWith the rapid development of social economy； it demands the better of water supply' s quality and reliability o

3、f water supply system. Meanwhile energy resources are seriously lack. So it is inevitable tendency to design water supply system which has high function and saves on energy well， with help of advanced technique of automation， control and communication. At the same time this system can adapt differen

4、t water supply fields.According to the requirement of China's urban water supply, this paper designs a set of water supply system of frequecey control of constant voltage based on PLC. It is consist of the variable frequency and speed regulation， PLC， PID control system for the control system. I

5、t controls the outcome of the pumps. The generator pumps are consist of parallel three pumps， and the power come from variable frequency and speed regulation or power grid. According to the water supply of constant pressures outcome water press and flux， the control system control the variable frequ

6、ency and speed regulation， parallel pumps speed and cut over， cause the system move in the best rational situation， assure according to wants supply water. This design has many merits such as save energy.In this paper，the control principle of VVVF providing-water system is introduced，we use PLC to c

7、arry on logic control and use inverter to modulate pressureThrough PID control principle .we realize Closed-loop control in VVVF Providing-water SystemThe result indicates that the system has the stable pressure，simple structure，and reliable workKey words：variable frequency and speed regulation；wate

8、r supply of constant pressure；PID control system；PLC目 录论文总页数：53页1 引言11.1 课题背景及意义11.2 供水技术及其发展11.3 恒压供水系统国内外研究现状21.4 可编程控制器的发展及应用31.5 本文主要内容42 恒压供水系统介绍52.1 当前恒压供水方案比较52.2 恒压供水系统节能原理62.3 变频器介绍82.3.1变频器的基本结构82.3.2 变频器的分类及工作原理92.3.3 变频器的操作方式及使用92.3.4 变频器调速原理102.4 可编程控制器112.4.1 可编程控制器的定义112.4.2 可编程控制器的组成

9、112.5 供水系统中的水锤效应123 变频恒压供水系统方案设计133.1 变频恒压供水系统构成133.2变频恒压供水系统运行流程153.3 水泵切换条件分析163.4 泵站的设置及系统控制要求173.5 控制系统地址分配174 变频恒压供水系统硬件设计194.1 PLC及其扩展模块194.2 变频器204.3 水泵机组224.4 压力传感器224.5 液位变送器224.6 泵自动/手动控制设计235 变频恒压供水系统软件设计255.1 系统软件设计分析255.2 系统软件设计265.2.1系统初始化模块275.2.2 增、减泵判断和相应操作模块285.2.3 水泵的软启动模块285.2.4 各水泵变频运行控制模块295.2.5 各水泵工频运行控制模块305.2.6 报警及故障处理模块305.3 系统程序编制316 系统仿真326.1 数字PID控制技术326