Constant pressure water supply system based on PLC and variable frequency control

ZHANG Ying1， ZHOU Ju1，YANG Pu-qiong2
（1. School of Mechanical Engineering， University of South China， Hengyang 421001， China；
2. School of Electrical Engineering， University of South China， Hengyang 421001， China）

Abstract： In order to solve the problems of a big investment，space occupancy，and low efficiency on the traditional water supply system，a constant pressure water supply system based on programmable logic controller（PLC） and variable frequency control was designed. In the system，the speed of pump motor was controlled by PLC-based inverter. It kept constant pressure piping. After analysis of the principle，the method of hardware and the software was given．Remote control by visual motoring interface was designed by MCGS. The practice results show that the system ensures the water quality，strengthens the ability of troubleshooting，reduces resource waste.
Key words： programmable logic controller（PLC）； inverter； constant pressure water supply