ABSTRACT
According to the requirement of China's urban water supply, this paper
designs a set of water supply system of frequecey control of constant voltage
based on PLC, and have developed good operation management interface using
Supervision Control and Data Acquisition.The system is made up of PLC,
transducer,units of pumps,pressure sensor and control machine and so on.
This system is formed by three pump generators,and they form the
circulating run mode of frequency conversion. With general frequency converter
realize for three phase pump generator soft start with frequency
control,operation switch adopts the principle of”start first stop first”. The
detection signal of pressure sensor of hydraulic pressure,via PLC with set value
by carry out PID comparison operation,so,control frequency and the export
voltage of frequency converter,and then the rotational speed that changes pump
generator come to change water supply quantity,eventually,it is nearby to
maintain pipe net pressure to stabilize when set value. Through work control
machine the connection with PLC,with group form software consummately
systematic monitoring,have realized operation state development to show and
data,report to the police inquiry.
Keywords: variable frequency speed-regulating, constant-pressure water
supply, PLC, supervision control and data acquisition.
