Research On Full-Digital Driving System Of Coriolis Mass Flowmeter

Coriolis mass flowmeter is a late-mode flow measurement instrument which can achieve high-precision direct mass flow measurement,and which is widely used in various industries. However, most of the products of Coriolis mass flowmeter are still using the analog and semi-digital driving approach, which driving ability is limited, easily affected by noise, resulting in the flow tube can’t vibration steady rapidly, even stop vibrate to abnormal measurements.The full-digital driving scheme were researched in this paper, and through aspects such as the algorithm and simulation comparison of different driving scheme, the software and hardware design and system test analysis.The details are as follows:(1)Comparison of algorithm and Simulation of different driving scheme Described the two driving scheme which is widely used currently, and Compared of the two driving scheme by Simulink,analysis of their driving deficiencies, full-digital driving scheme were drawing off which is this topic research, through algorithm research and simulation verify the advantage of this scheme. In addition, interference signal were joined in three kinds of simulation model,which makes the simulation results more convincing.(2) Full-digital driving test system hardware and software design solutions. Hardware design adopts module design method, mainly includes power management, signal acquisition and processing,driving signal synthesis, DAC and the peripheral interface module, introduced in detail the design method of each module and summarizes the design experience.In addition,This paper selects TI floating-point DSP chip TMS320F28335 as the main controller, effectively improved the accuracy of the measurement system. The overall design of the system software were first provided in the software design part, and then according to the system operation order introduced the signal acquisition,improved frequency estimation algorithm based on zero-crossing detection,amplitude control algorithm based on fuzzy-PI, and designed the program flow chart of each part.(3) System test analysis. important function of the full-digital driving test system which self-developed, including power module stability and safety testing, frequency estimate precision testing, amplitude control algorithm control effect and the driving signal synthesis test, the test results show that the testing system can realize the function of each part, and can meet the design requirements of this topic.The special feature at this topic is the application of the amplitude control algorithm based on fuzzy-PI of the full-digital driving system, System test results show that,Compared with the amplitude control algorithm researched more,the fuzzy PI control algorithm can achieve control rapidly,and have greater precision. In addition, the full-digital drive scheme of this research overcomes the problems about limited driving ability, easily affected by noise and so on. The above analysis shows that, the research methodology and the test system in this paper is effective and feasible.