基于PLC与变频器的恒压供水系统设计

Constant pressure water supply system based on PLC and frequency converter

针对传统供水系统压力不稳定、能源浪费严重、自动化程度低等缺点,设计了一种基于PLC与变频器的恒压供水系统。该系统利用变频器、PLC和PID调节器构建了闭环自动调节恒压供水系统。供水系统的控制目标为总管道的出水压力,将给定压力值和反馈的出水压力值相比较,把偏差值送到CPU中进行处理,从而发出控制指令来调整水泵电动机投入运行的台数和调节水泵电动机的转速,以保持总管道出水压力的稳定。通过PLC与变频器自动地调节水泵台数的增减、水泵电动机的转速,既避免了能量的空耗,又防止了电动机启动时电流对供水设备的影响,实现了恒压供水。

Traditional water supply system is instability,energy consuming and low degree of automation.Focus on the shortages,this paper presents a constant pressure water supply system based on PLC and frequency converter.The proposed water supply system which could be adjusted automatically is a closed loop system with PLC,frequency converter and PID regulator.The system inputs the difference between the given pressure value and the feedback water pressure value into the CPU,which would determine the number of operating pumps and the speed of them to stabilize the water pressure of the main pipe.The system could adjust the number of pumps and the speed of the pump motor automatically,which would prevent energy wasting and avoid the damage of the start current,and achieve the constant pressure water supply.