摘要:在当今社会，随着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，而人们对水资源的利用率很低，采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将成为必然的趋势。

　　　本论文研究的是变频恒压供水系统。恒压供水系统以PLC和变频器为核心进行设计，借助于PLC强大而灵活的控制功能和内置PID的变频器优良的变频调速性能，实现了恒压供水的控制，并实现上位机组态王的实时监控该系统采用PLC控制变频器进行PID调节，按实际需要随意设定压力给定值，根据压差调整水泵的工作情况，改变变频器输出频率，随时切换水泵的工作数量，实现恒压供水，使给水泵始终在高效率下运行，提高了供水的可靠和稳定。

　　　本论文的变频恒压供水系统已在国内许多实际的供水控制系统中得到应用，并取得稳定可靠的运行效果和良好的节能效果。经实践证明该系统具有高度的可靠性和实时性，极大地提高了供水的质量，并且节省了人力，具有明显的经济效益和社会效益。

关键字：变频调速；恒压供水；PLC；组态王；监控系统

Abstract:In today's society, as people of water supply quality and water supply system reliability requirements are improving; Plus the current energy shortages, and people to the utilization of the water resources is low, and the use of advanced automation technology, control technology and communication technology, the design of high performance, high energy saving, can adapt to different areas of constant pressure water supply system will become an inevitable trend 

　　This paper studies the variable frequency constant pressure water supply system. Constant pressure water supply system to PLC and inverter as the core design, powerful and flexible resort PLC control function and built-in PID frequency converter of variable frequency speed of excellent performance and to realize the constant pressure water supply control, and realize the computer is added.the real-time monitoring of king state this system is used to control the PLC PID frequency converter for regulation, according to the practical needs pressure setting at the given value, according to the pressure difference adjustment of water pump work, change the frequency converter frequency, change to pump the amount of work, realize constant pressure water supply, make the pump running in high efficiency always, improve water supply reliable and stable. 

　　　This paper frequency conversion of constant pressure water supply system has set up a file in the domestic many practical water supply control system applied in, and to have the effect of operation of reliable and good effect in energy saving. The practice shows that the system has high reliability and real-time, greatly improving the quality of the water supply, and save the human, has the obvious economic benefits and social benefit.

Key Words: VF speed; constant pressure water supply; PLC; kingview; monitor and control- system