The control system of high temperature melt pump consists of programmable controller, frequency converter, motor, temperature sensor, pressure sensor, solid state relay and heating rod. Temperature sensors collect the temperature signals of inlet, pump and outlet of high temperature melt pump. The temperature signals in these three areas are fed back to PLC through PID operation, and then the heater rods in the three temperature areas are controlled by PLC to achieve constant temperature control. Pressure sensors collect the pressure signals of inlet and outlet of high temperature melt pump, and the pressure is controlled by the closed control of solid state relay. The force signal is fed back to the PLC through PID operation and the analog output module outputs the analog signal to the upper computer frequency converter and the local frequency converter respectively. The speed of the motor is controlled by the frequency converter to realize the pressure regulation. Touch screen is connected to PLC through RS485 communication cable. Target values of temperature and pressure can be set by touch screen, and current temperature and pressure readings can be displayed. In debugging time, various parameters of PID can be easily modified by touch screen, so that the PID operation can largely meet the control accuracy requirements of the system.
