The function of the frequency converter is to provide a variable frequency power supply for the motor to realize the stepless speed regulation of the motor, so that the water pressure of the pipe network changes continuously. The task of the sensor is to detect the water pressure of the pipe network, and the pressure setting unit provides the system with the expected value of the water pressure that meets the needs of the user. After the pressure setting signal and pressure feedback signal are input to the programmable controller, they are calculated by the internal PID control program of the programmable controller and output to the frequency converter a speed control signal. Another method is to send the pressure setting signal and the pressure feedback signal to the PID loop regulator. After the PID loop regulator performs calculations inside the regulator, it outputs a speed adjustment signal to the inverter.
The variable frequency constant pressure water supply system is mainly composed of a pool, a variable frequency control cabinet, a pressure sensor, a centrifugal pump, and a touch screen display. The frequency conversion control cabinet is composed of circuit breakers, frequency converters, contactors, intermediate relays, and PLCs.
Principles for selection of water supply system
(1). The storage tank capacity should be greater than the maximum water supply per hour.
(2). The pump lift should be greater than the actual water supply height.
(3). The sum of the pump flow rates should be greater than the actual maximum water supply.
(4). Frequency conversion control cabinet selection:
The model and number of pumps can be determined according to the water supply volume and water supply height, and then the control cabinet can be selected.