Constant pressure water supply system design and simulation based on PLC control

For the need to build an intelligent building life and fire water supply system,a design was proposed,which was composed of PLC,frequency converter and PID regulator and could achieve AC dual-constant-pressure,dual-frequency-convert close-loop speed governing control.According to water-out pressure and flow rate,the system can provide constant pressure alternating quantity water supply by controlling the speed of motor unit and switchover from variable frequency to power-frequency.Simulation of the above system in MCGS showed that the system has pressure stability,simple structure and good reliability.