Multi-parameter Flow Transmitter Design And Implementation

Flow measurement is widely applied in life, For example, Transportation, Trade settlement Industrial production control, Scientific experiments, Biological engineering, and all aspects of people’s life. With people on flow measurement accuracy requirements are high, to improve traditional of flowmeter has become a very important practical significance.In this paper, mainly for the following research and design, based on the actual function of multiple parameter flow transmitter the implementation of the requirements.1. Search a lot of literature about multi-parameter flow transmitter. Studied several major flow-meter measurement principle, and in-depth analysis of the research status of smart differential pressure transmitter.2. Proposed a new differential capacitance measurement solution, FPGA-based and equal precision measuring capacitance. Analysis of the principle of equal precision measuring capacitance. Improved the capacitive sensor pulse width modulation circuit which current used. And analyzes and equal precision measuring capacitance error.3. To study the internal structure of the differential pressure flow-meter. Analysis of the measurement principle of differential pressure mass flow meter. Analysis orifice flow-meter measurement formula based on the relevant principles.4. In terms of hardware the article is in line with low power consumption, ease of use, integration, and other principles of design. Use modular design, design a multi-parameter flow transmitter hardware circuits based on microcontroller MSP430F149. Including sensor data acquisition, and other precision measuring differential conversion circuit, keyboard circuit, LCD circuits, communications interface circuits, voltage conversion circuit and other parts.5. Software part of this paper is make the whole process divided into different modules, for make the program with accessibility, versatility and maintainability. And to do so there is an advantage that can make the program portability. When the site needs to be changed is only to change on the corresponding module enables the instrument to work, without having to rewrite the entire program, which makes the instrument more practical.Finally, validation of this new method of measuring capacitance of the differential pressure sensor is higher than the accuracy of several precision capacitance measuring method currently used which can be achieved 0,2pf, by examining the theoretical analysis and experimental data. Proved the superiority of this capacitance measurement method. The multi-parameter flow transmitter measurement accuracy is also improved by using this measurement method can be achieved 0.5%.