一体化磁阻式金属管浮子流量计的研制

发布时间：2018-01-18 10:19

本文关键词：一体化磁阻式金属管浮子流量计的研制　出处：《天津大学》2012年硕士论文　论文类型：学位论文

【摘要】：在过程控制、医药卫生、能源计量及日常生活等领域中,流量是最重要的检测控制信号之一。浮子流量汁是一种经典的变面积式流量计。因其具有构造简单,工作可靠,价格低廉,对前后直管段要求不高等优点,被广泛用于气体、液体、蒸汽流量的测量中。本论文研究的是基于MSP430系列单片机的一体化磁阻式金属管浮子流量计的研制。通过磁路耦合将浮子的纵向位移转换成外部径向充磁磁钢(简称外磁钢)的角位移,利用磁阻传感器检测外磁钢的角位移,利用温度传感器检测外环境温度,利用温度、压力传感器检测介质温度和压力,由MSP430系列单片机进行A/D采样、软件算法处理、PWM波输出、液晶显示等,通过RS485标准通讯接口实现下位机设置和流量计的标定。此外,系统增加外扩看门狗模块和掉电保护电路以提高可靠性。为了满足现场要求,本论文共设计了两种方案,一种采用直流24 V供电,带4~20 mA两线制模拟电流输出的设计方案,另一种是采用3.6V电池供电的设计方案。采用模块化程序设计思想,在优化主程序的基础上,实现了流量信号采集与计算、瞬时流量/累计流量显示、PWM波输出、上下位机通信、仪表参数存储等功能的软件设计。分析浮子流量计的标定曲线线性度差的原因,从软件上解决了因标定曲线非线性造成的测量精度下降的问题,并通过实流实验验证了所提出的分区最小二乘法拟合能降低或消除机械加工对金属管浮子流量计测量精度造成的影响的结论。在实流实验方面,根据磁阻传感器方案生产了两台金属管浮子流量计样机,口径为DN25和DN100。在天津大学过程检测与控制实验室水流量标准装置上分别对其进行标定和检定,其精度等级均为1.0级。
[Abstract]:In the field of process control , medical and health , energy metering and daily life , the flow is one of the most important detection control signals . The float flow is a classical variable area flow meter . Because of its simple structure , reliable operation and low price , it is widely used in the measurement of gas , liquid and steam flow . This paper deals with the development of integrated reluctance type metal tube float flow meter based on MSP 430 series single chip microcomputer . By magnetic circuit coupling , the longitudinal displacement of the float is converted into the angular displacement of outer radial magnetizing magnetic steel ( hereinafter referred to as outer magnetic steel ) . The temperature and pressure of the outer magnetic steel are detected by using the magnetic resistance sensor . The temperature and pressure of the medium are detected by using the temperature sensor . The temperature and pressure of the medium are detected by using the temperature sensor . The setting of the lower machine and the calibration of the flowmeter are realized by using the RS485 standard communication interface . In addition , the system increases the external expansion watchdog module and the power down protection circuit to improve the reliability . In order to meet the requirements of the site , the thesis designs two schemes , one using DC 24 V supply , two - wire analog current output with 4 - 20 mA , and the other is a design scheme that uses a 3.6 V battery to supply power . The software design of flow signal acquisition and calculation , instantaneous flow / cumulative flow display , PWM wave output , upper and lower machine communication and instrument parameter storage is realized based on the principle of modularization programming . The reason for the linearity of calibration curve of the float flowmeter is analyzed . The problem of decreasing the measurement accuracy caused by the nonlinearity of the calibration curve is solved from the software , and the conclusion that the proposed zoning least square fitting can reduce or eliminate the effect of machining on the measurement accuracy of the metal tube float flowmeter is verified by the real flow experiment . In the field of real flow experiment , the prototype of two metal tube float flowmeter is produced according to the scheme of magnetoresistive sensor . The caliber is DN25 and DN100 . The calibration and verification are carried out respectively on the water flow standard device of Tianjin University process detection and control laboratory , and the precision grade is 1.0 .

【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP212.11;TP368.1

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