INSTRUMENTACÃO ANALÓGICA E MICROPROCESSADA APLICADA À LEITURA DE VAZÃO

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INSTRUMENTACAO ANALOGICA E MICROPROCESSADA APLICADA A
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LEITURA DE VAZAO

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Abstract— The main goal of this job is to develop an electronic system able to measure a real time water flowing using only fixed parts. Therefore, it was built a Venturi’s tube, with two access points for reading the pressure. The electronic system development is divided in four main parts: a sensor, an analog electronic, a digital electronic with a microcontroller and a display. The flow measurement is resultant of analysis done by a differential pressure sensor connected to the Venturi’s tube. The sensor answers, by electric voltage, to the differential pressure related to the flow via the Bernoulli’s principle. Analog circuits directly connected into a microcontroller ARM cortex M3 (STM32F107VC) adjust the sensor output voltage. The kit STM3210C EVAL was utilized as a development board in this project. The flow measurement result is indicated by a 20x4 display.
Finally, a conventional volumetric water meter compares all the provided output data by electronic system.
Keywords—

differencial pressure sensor, Venturi’s tube, Bernoulli’s principle.

Resumo— O presente trabalho tem como principal objetivo o desenvolvimento de uma instrumenta¸˜o eletrˆca o nica capaz de medir vaz˜o de ´gua, em tempo real, sem a utiliza¸˜o de pe¸as m´veis. Para tanto, foi constru´ a a ca c o ıdo um Tubo de Venturi, com dois pontos de acessos para a leitura de press˜o. O desenvolvimento do sistema elea trˆnico ´ dividido em quatro partes principais: o sensor, a eletrˆnica anal´gica, a eletrˆnica digital juntamente o e o o o com um microcontrolador e o display de impress˜o de dados de sa´ a ıda. A medi¸ao de vaz˜o ´ resultante da leitura c˜ a e efetuada por um sensor diferencial de press˜o conectado ao Tubo de Venturi. O sensor responde, em forma a de tens˜o el´trica, a diferen¸a de press˜o que ´ relacionada com a vaz˜o atrav´s do princ´ a e c a e a e ıpio