基于plc的恒压变频供水系统设计.docx

恒压变频供水系统设计摘 要本论文设计了一套基于PLC的恒压变频供水系统。变频恒压供水系统由可编程控制器、变频器、水泵机组、压力传感器等构成。可为小区高楼居民提供良好的生活用水件。本系统包含三台水泵电机，它们组成变频循环运行方式。利用PLC控制接触器来控制水泵工作在工频或变频状态。正常供水时总有一台水泵工作在变频状态。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。本系统在提供优良的供水条件的同时，还有节约能源，易于管理维修的优点。PLC简单而强大的编程功能,使得在不同需求时，可以在本系统的基础上增加相应的功能。如小区发生火灾险情的时候可以智能切换为全压供水，为居民的生命财产提供多一层的保障。关键词：变频调速，恒压供水，PLC，PID算法，变频器The Design of Constant Pressure Frequency Conversion Water Supply SystemABSTRACTThis paper designs a set of constant pressure frequency conversion water supply system based on PLC. Variable frequency constant pressure water supply system consists of programmable controller, inverter, pump, pressure sensor and so on. Provide high life quality of water condition for High-rise building households.This system includes three water pump motor, making up frequency conversion circulation operation. Controlling water pump working at power frequency or frequency conversion by PLC control contactor . At any time, there is a water pump working in variable frequency state. The pressure sensor test the current pressure signal, do PID arithmetic after compared the numerical send to PLC with the set value. Then it can control the output voltage and frequency of the inverter, and change the water pump motor speed to change water supply. Eventually maintain the pressure of the pipe network pressure stability near the set point. This system provides excellent water supply conditions , at the same time ,taking the advantages of energy saving, easy management and maintenance. PLC is simple and powerful programming capabilities when different demand can increase the corresponding function on the basis of this system. Such as a fire danger can intelligent switch for all pressure water supply, to peoples life and property for an extra layer of security.PLC programming simple and powerful. What’s more, If there are some special requirements, corresponding function can be added based this system. For example, fi