基于PLC及变频调速小区恒压供水系统设计

Design of Constant Pressure Water Supply System Based on PLC and Variable Frequency Speed Regulation

结合我国现代城市小区的供水状况,提出了基于PLC及变频调速的小区恒压供水系统设计。阐述了变频调速恒压供水系统的构成及工作原理、系统硬件选择、PLC程序设计以及变频器参数设定等。系统由一台变频器拖动四台水泵启动,PLC控制切换,压力传感器检测网管压力,根据压力大小由PLC进行PID控制,能够根据测量值和压力给定值的偏差对变频器的输出电压和频率进行实时控制,根据变频器的输出频率进而改变水泵的转速,保证网管压力恒定的条件下调节出水口流量的大小。系统具有抗干扰能力强、系统可靠性高、高效节能、配置灵活、自动化水平高、安全可靠等特点。

In this paper,based on the water supply situation of our country＇s modern urban district,the system of constant pressure watersupply based on PLC and variable frequency speed regulation is designed. This paper focuses on the structure and working principle ofvariable frequency speed regulation of constant pressure water supply system, the selection of system hardware, the design of PLCprogram and the setting of converter parameters. In this system,four pumps are dragged by a frequency converter,PLC control switch,the pressure is detected by pressure sensor in the network,PID is carried out by PLC according to the size of the pressure,according tothe deviation of the measured value and a given value, the output of voltage and frequency of the inverter is real-time controlled, thepump speed is changed according to the output frequency of the inverter, the size of outlet flow is regulated under the condition of aconstant pressure. The system has strong anti-interference ability, high system reliability, high efficiency and energy saving, flexibleconfiguration,high level of automation,safe and reliable.