(1) Connect the calibration process so that the flowmeter and the volumetric tube are connected together to form a calibration system;
(2) The operator enters various parameters of the calibrated flowmeter in the calibration screen on the IPC, such as the maximum flow rate, minimum flow rate, and flowmeter coefficient of the flowmeter. Then click the "Calibration" button with the mouse, and start calibration after confirmation;
(3) The control system starts the ball-throwing mechanism, and the ball-throwing runs 3 times, so that the temperature of the liquid in the entire calibration system tends to be stable and the gas is removed, and then enters the calibration process;
(4) The high-speed counting module of PLC reads the pulse amount of the flowmeter to be tested, and calculates the instantaneous flow value of the liquid in the current volume tube. According to the input flowmeter parameter value, the analog output module of PLC and the inlet of the volume tube The single-loop PID regulation system composed of regulating valves adjusts the current flow rate of the liquid in the volume tube to 50% of the maximum flow rate of the tested flowmeter;
(5) According to the specified calibration point, after the flow is stable, start calibration: When the elastic ball passes the first detection switch D1, the pulse counter of PLC starts counting; when the elastic ball passes the second detection switch D2, the counter stops Count, and count the number of pulses from the flowmeter between the two detection switches. After that, the PLC calculates the cumulative value of the liquid according to the pulse/flow ratio;
(6) Repeat the above calibration procedure, and calibrate according to the maximum flow rate, 40% of the maximum flow rate and the minimum flow rate of the flowmeter. Repeat the measurement for each flow point no less than 3 times, and calculate the liquid cumulative value for each calibration.