The Design And Implementation Of Level Transmitter Based On Magnetostrictive

In the traditional industry measurement, the measurement instruments adopts a direct-contact way. Thus, due to mechanical friction or chemical erosion, not only is the mechanical life expectancy of instrument significantly reduced, but also the accuracy of measurement will be affected. With the wide applications of liquid level measurement in industrial automation, it is quite necessary to research and produce a high-performance, non-contact liquid level transmitter.Under the action of external magnetic field, both the size and the shape of strong magnetic material will be greatly changed, which is usually called the magnetostrictive phenomenon. Aiming at the specificity of non-contact level measurement, this thesis has developed a design method about magnetostrictive level transmitter based on the magnetostrictive effect. The whole design scheme consists of hardware design, software design, analysis and performance test. Among them, the design of hardware circuit adopts an independent modular design method, including control communication module, analog circuit module, power module and LCD display module. Communication module is divided into three parts: the data communications between CPU and AD421,A5191 and TDC, which also involves three communication principles, i.e., I2C, UART, and SPI. In the design of software, we introduce the pin configuration of software, analyze the whole design process of software, and also present the configuration, measurement mode, and calculation process of the TDC. In the simulation and performance test, PSPICE is utilized to simulate analog circuit, and the compared test is made for difference input source and amplification numbers or RC parameters, which verify the reasonableness of the proposed circuit design. And then, the analysis on both input and output results of every part is also made according to the debugging.Finally, the test on the performance, such as repeatability, stability, non-linear nature and power-down testing is made. It is shown that the errors of both repeatability and stability are lower than five ten thousandth. Moreover, both the nonlinearity and the performance of resistance to power-down are also excellent. These fully achieve the design requirements.