大学本科毕业设计基于PLC的变频调速恒压供水系统自动化等专业 2.doc

PAGE 摘要 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, 并利用组态软件开发良好的运行管理界面。变频恒压供水系统由可编程控制器、变频器、水泵机组、压力传感器、工控机等构成。 本系统包含三台水泵电机，它们组成变频循环运行方式。采用变频器实现对三相水泵电机的软启动和变频调速，运行切换采用“先启先停”的原则。压力传感器检测当前水压信号，送入PLC与设定值比较后进行PID运算，从而控制变频器的输出电压和频率，进而改变水泵电机的转速来改变供水量，最终保持管网压力稳定在设定值附近。通过工控机与PLC的连接，采用组态软件完成系统监控，实现了运行状态动态显示及数据、报警的查询。 关键词：变频调速，恒压供水，PLC，组态软件 ABSTRACT According to the requirement of Chinas urban water supply, this paper designs a set of water supply system of frequecey control of constant voltage based on PLC, and have developed good operation management interface using Supervision Control and Data Acquisition.The system is made up of PLC, transducer,units of pumps,pressure sensor and control machine and so on. This system is formed by three pump generators,and they form the circulating run mode of frequency conversion. With general frequency converter realize for three phase pump generator soft start with frequency control,operation switch adopts the principle of”start first stop first”. The detection signal of pressure sensor of hydraulic pressure,via PLC with set value by carry out PID comparison operation,so,control frequency and the export voltage of frequency converter,and then the rotational speed that changes pump generator come to change water supply quantity,eventually,it is nearby to maintain pipe net pressure to stabilize when set value. Through work control machine the connection with PLC,with group form software consummately systematic monitoring,have realized operation state development to show and data,report to the police inquiry. Keywords: variable frequency speed-regulating, constant-pressure water supply, PLC, supervision control and data acquisition. 目录 TOC \o 1-2 \h \z \u HYPERLINK \l _Toc233100241 1 绪论 PAGEREF _Toc233100241 \h 1 HYPERLINK \l _Toc233100242 1.1 课题的提出 PAGEREF _Toc233100242 \h 1 HYPERLINK \l _Toc233100243 1.2 变频恒压供水系统的国内外研究现状 PAGEREF _Toc233100243 \h 3 HYPERLINK \l _Toc233100244 1.3 PLC概述 PAGEREF _Toc233100244 \h 5 HYPERLINK \l _To