Research And Development Of High Precision Flowmeter Based On HART Protocol

With the development of modern industry, the automation system gets much more huger and complex. In addition, with the expansion of its application fields, it proposed higher requirements for flow meter. Combined with one company's technical innovation project, this paper researches and develops a special high-precision flow measuring device which is based on ASME low-βvalue of long-necked nozzle.It is used in Turbine performance testing of plant. The flow meter that this paper studied and developed is based on the principle of difference pressure flow transmitter. To achieve a mass flow measurement, it collects three signals (difference pressure, temperature, pressure) to calculate the fluid flow.The paper first introduces the design requirements of the flow meter and gives the entire design program according to the requirements; Then it introduces details of the meter's hardware and software design, that including chip selection, analog-digital conversion circuit design, system power supply circuit design, digital-analog conversion circuit design and HART communication module design as well as the processes design of some function module. Besides, it gives a brief introduction of anti-interference and reliability design which used the hardware and software methods; Then it gives the introduction of the HART protocol and the development of host communication software. Finally, the paper tests the communication and precision of the prototype.The results show that both the precision and the functions are meet the requirements.