Design Of Electromagnetic Flowmeter Based On MSP430F149

Electromagnetic flowmeter which is based on Faraday's induction law, is a velocity-type flowmeter. In numerous flow measurement instruments, electromagnetic flowmeter with many unique characteristics is widely used in industry on a variety of specific conductivity of liquid measurement. In this paper, electromagnetic flowmeter at home and abroad for the development of the status and trends is introduced simply. Based on a brief explanation of the electromagnetic flowmeter measurement principle, this article uses MSP430F149 MCU to design a kind of electromagnetic flowmeter with low frequency rectangular wave excitation. The diagram of the overall design, some hardware and software control flow chart are given.In the hardware system, mainly introduced the exciting circuit, signal processing circuit, man-machine interfaces, signal input and output circuits and the method of empty pipe detection. System uses precision instrument amplifier INA114, and with high precision 16-bit ADC ADS8320 acquisition and processing of the traffic signals to improve detection accuracy of the instrument.128×64 liquid crystal display module JRM-12864R5 is used to display data. Input and output optical isolation circuit technology is applied to improve system reliability and anti-interference capability. Selects RS-485 standard bus to achieve the instrument communication, increased the system openness and communication function. Simultaneously the measuring appliance also has standard analog current 4-20mA, frequency /pulse signal and the upper and lower alarm signal output.Uses the MSP430 assembly language in the software design, implemented the modular design, the paper gives the software system design flow chart and part of the subroutine flow chart. Finally, the PCB was designed under a full consideration of anti-interference and the measure which the software and hardware unified was used to enhance the equipment anti-interference.This design of electromagnetic flowmeter has been put into production, the practical application shows that the instrument has high-precision, low power, reliability, and other characteristics to meet the design requirements. This project's development, has certain reference value to electromagnetic flowmeter's development work.