【正文】 ion energy conservation effect etc， this paper introduced the frequency conversion velocity modulation technology in the water supply system application. This set of system has the functions like automatic constant pressure operation by using variable frequency, automatic work frequency operation， and the mode of longrange control by hand and the onthespot control by hand etc. The system has solved the problem existing in the traditional way of water supply. And extended to municate between puter and PLC functions. This paper has finished setting up the munication between upper and lower puter. At the same time ,this paper also realize the longrange monitoring and fault reporting for water supply system through munication strengthen the reliability,promotes the systematic overall performance. Key words Constant pressure watersupply Variable velocity Variable frequency PLC(Programmable controller) XII 目 錄 摘 要 .......................................................................................................................... I 摘 要（英文） ....................................................................................................... XI 第 1 章 緒論 ............................................................................................................... 1 課題來源及研究意義 .................................................................................... 1 課題來源 .............................................................................................. 1 研究意義 .............................................................................................. 2 國內(nèi)外變頻供水系 統(tǒng)研究現(xiàn)狀及發(fā)展趨勢 ................................................ 2 國內(nèi)外變頻供水系統(tǒng)研究現(xiàn)狀 .......................................................... 2 變頻供水系統(tǒng)發(fā)展趨勢 ...................................................................... 4 課題研究對象及主要研究內(nèi)容 .................................................................... 4 課題研究對象 ...................................................................................... 4 主要研究內(nèi)容 ...................................................................................... 5 第 2 章 供水系統(tǒng)主電路設(shè)計 ................................................................................... 6 供水方式的選擇 ............................................................................................ 6 系統(tǒng)方案選擇 ................................................................................................ 6 供水系統(tǒng)主電路設(shè)計 .................................................................................... 8 主電路圖設(shè)計 ...................................................................................... 8 水泵電機(jī) ............................................................................................ 10 變頻器 ................................................................................................ 13 交流接觸器 ........................................................................................ 15 過載保護(hù) ............................................................................................ 16 降壓啟動及自耦變壓器選型 ............................................................ 18 水泵調(diào)速運行的節(jié)能性分析 ...................................................................... 18 小結(jié) .............................................................................................................. 20 第 3 章 供水系統(tǒng)控制電路設(shè)計 ............................................................................. 21 供水系統(tǒng)控制電路圖設(shè)計 .......................................................................... 21 供水系統(tǒng)控制原理圖設(shè)計 ................................................................ 21 供水系統(tǒng)運行指示圖設(shè)計 ................................................................ 22 XIII PLC 及其擴(kuò)展模塊選型 ............................................................................. 23 PLC 選型 ........................................................................................... 23 模擬量輸入輸出模塊選型 ................................................................ 24 數(shù)據(jù)通信模塊 .................................................................................... 24 PLC 的 I/O 端子分配及變頻器接線 .......................................................... 24 PLC I/O 端子分配 ............................................................................. 24 變頻器接線 ........................................................................................ 26 壓力變送器選型 .......................................................................................... 26 控制電路中間繼電器選型 ......................................................................... 27 PLC 用隔離變壓器選型 ............................................................................. 27 鑒頻鑒相器的選型 ...................................................................................... 28 “倒泵功能”在恒壓供水系統(tǒng)中的應(yīng)用 ................................................... 28 手動控制在恒壓供水系統(tǒng)中的應(yīng)用 .......................................................... 29 控制算法在恒壓供水系統(tǒng)中的應(yīng)用 ........................................................ 29 小結(jié) ............................................................................................................ 30 第 4 章 供水系統(tǒng) PLC 軟件設(shè)計 ............................................................................. 32 系統(tǒng)水泵運行狀態(tài)及轉(zhuǎn)換過程分析 .......................................................... 32 供水系統(tǒng)程序設(shè)計 ...................................................................................... 33 供水系統(tǒng)程序流程圖設(shè)計 ................................................................ 33 供水系統(tǒng)主程序設(shè)計 ........................................................................ 35 供水遠(yuǎn)程監(jiān)控 系統(tǒng)設(shè)計 .............................................................................. 38 監(jiān)控系統(tǒng)硬件構(gòu)成 ............................................................................ 38 PLC 通信程序設(shè)計 ........................................................................... 39 計算機(jī)通信程序設(shè)計 .