【正文】 .................. 43 參考文獻(xiàn) ................................................................................................................... 44 附 錄 ....................................................................................................................... 45 XIV CONTENTS Abstract（ Chinese） ................................................................................................. I Abstract .................................................................................................................... XI Chapter1 Introduction .............................................................................................. 1 Topic source and research significance .......................................................... 1 Topic source ......................................................................................... 1 Research significance ........................................................................... 2 Domestic water system frequency research situation and development trend...................................................................................................................... 2 Domestic water system frequency........................................................ 2 Frequency conversion water supply system development trend .......... 4 Research objects and research content ........................................................... 4 Research object .................................................................................... 4 The main research contents .................................................................. 5 Chapter2 The main circuit design water system .................................................... 6 The choice of the ways of water..................................................................... 6 System scheme selection ................................................................................ 6 The main circuit design water system ............................................................ 8 Main circuit design ............................................................................... 8 Pump motor ........................................................................................ 10 Inverter ............................................................................................... 13 Ac contactor ....................................................................................... 15 Overload protection ............................................................................ 16 Stepdown start and selection of the transformer ............................... 18 The water saving speedregulating operation............................................... 18 Summary ...................................................................................................... 20 Chapter3 Water supply system control circuit design ......................................... 21 Water supply system control diagram design ............................................... 21 Water supply system control diagram design ..................................... 21 Water supply system operation indicator diagram design .................. 22 XV PLC and its extension module selection ...................................................... 23 PLC selection ..................................................................................... 23 Analog input and output module selection ......................................... 24 Data munication module ............................................................. 24 PLC distribution of I/O terminals and Inverter wiring................................. 24 PLC distribution of I/O terminals ...................................................... 24 Inverter wiring .................................................................................... 26 Pressure transmitter selection ....................................................................... 26 Intermediate relay type of Control circuit .................................................... 27 The isolated transformer selection of PLC................................................... 27 Phase/frequency discriminator selection ...................................................... 28 Pour pump function in the constant pressure water supply system application .......................................................................................................... 28 Manual control in the constant pressure water supply system application .. 29 Control algorithm in the constant pressure water supply system application .......................................................................................................... 29 Summary .................................................................................................... 30 Chapter4 Water supply system of PLC software design ..................................... 32 Pump system and conversion process analysis ............................................ 32 Water supply system programming .............................................................. 33 Water supply system program flowchart design ................................ 33 Water system design of the program .................................................. 35 Water remote monitoring system design ...................................................... 38 Monitoring system hardware.............................................................. 38 PLC munication program design................................................. 39 Computer munication program design ........................................ 40 Summary ...................................................................................................... 41 Conclusions .............................................................................