PLC控制变频调速恒压供水系统

介绍了自行设计的恒压供水系统，采用PLC进行逻辑控制，有用变频器进行压力调节。变频器、可编程控制器作为系统控制的核心部件，时刻跟踪管网压力与给定压力的偏差变化，经变频器内部PID运算，通过可编程控制器控制变频与工频切换，自动控制水泵投入的台数和电机转速，实现闭环自动调节恒压变量供水，在保持恒压下达到控制流量的目的，运行结果表明，该系统具有压力稳定，结构简单，工作可靠等特点。

A constant pressure water supply system using PLC and VVVF

A constant pressure water supply system was introduced to which used PLC to process the logic control and employed VVVF to adjust water pressure. Frequency converter and PLC are the key components of system control , They follow up the deviation between the pipe network pressure and preessure given. Through operation of PID and swi tc hover of frequency conversion and power frequenly was controlled by PLC,it conld automatically control number of water pump put into operation and speed of AC m otor for velizing automatic regulation of closeloop and suppling water un der constant pressure and variety runoff. The results indicated , it has lots of advantages of pressure constant , contructure simpleness and operation credibil ity.