Research On Calibration Facility Of Ultrasonic Water Meter

Ultrasonic water meters,based on the principle of ultrasonic wave,were a kind of electronic water meter for flow measurement.Which had a lot of advantages,such as high accuracy,good reliability,wide turndown ratio,no moving parts,small pressure loss,and installation at any angle,etc.,and were widely used in water works and residential district.However,at present the ultrasonic water meter calibration device is still based on the traditional calibration facility at home and abroad,could not meet the needs of the market.For solving problems,a complete set of ultrasonic flow meter calibration facility has been designed and researched.According to the features of ultrasonic water meters,the static mass method and master meter method were employed to implement,The facility including two sets of pumping systems,four different combinations of standard meters and two scales were designed.The adjustability and stability at different flow point verification was ensured and guaranteed.The method that three same caliber ultrasonic water meters were installed in series in the calibration facility,improved the test efficiency and ensured the accuracy was not reduced.In the hardware design of control system,the PLC and corresponding AD / DA modules were taken as the core to design pulse acquisition circuit,AD conversion processing circuit and the output driver circuit,to achieve pulse acquisition and instantaneous reading,to measure the temperature and pressure,to adjust the degree of opening of the control valve of the output switch,frequency converter and control valve.The control system included PC software and internal procedures in PLC,the PC software based on the.NET platform C# language has realized to read the internal data in PLC and control hardware to run and other functions.It mainly included: the parameter settings of detected meters,the parameter settings of test flow point,the main control interface,the data query and print interface,the other parameters settings.By mutual cooperation in each sub-interface,the entire system achieved reliable operation.PLC internal procedure completed pulse acquisition part,output driving part,AD and DA Settings section.Finally,by the uncertainty assessment of static mass method and master meter method,the equipment could reach the national requirements.According to a large number of experimental data,it has been proved that ultrasonic water meter calibration facility met the production needs.Meanwhile,the control system has advantages of high reliability,high automation,simple operation,and so on.