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基于CAN总线的弯管流量计测量系统的研究与设计
Research and Design for Elbow Flowmeter Measure System Based on CAN Field Bus
【作者】 于雪松;
【导师】 史锦珊;
【作者基本信息】 燕山大学 , 测试计量技术及仪器, 2004, 硕士
【摘要】 现场总线作为过程自动化、制造自动化等领域的现场智能设备之间的互连通信网络,建立了生产过程现场控制设备之间以及与更高控制管理层网络之间的互联。CAN 总线的数据通讯具有可靠、实时和灵活等突出特点,对改进智能仪表间的通信提供了一种可靠的解决方案。本文在深入分析了国内外弯管流量计研究现状的基础上,开发了一种集弯管流量传感器、转换器、积算仪于一体的 CAN 总线智能流量测量仪表与系统,并进行了各个环节的研究与设计。从弯管流量计测量基本理论入手,介绍了自由涡流理论和强制涡流理论,并分析和对比了它们的优缺点。在此基础上,选用了强制涡流理论与流量系数修正的方法,给出了数学模型,并对弯径比为 1.5 的弯管传感器进行了设计。应用新型微处理器、计算机软硬件以及现场总线技术,并提出了对差压、流体密度和管径 D 实时修正的补偿技术,对提高弯管流量计的测量精度起了重要的作用。还对标度变换、全自动校准、电源监视和掉电保护进行了分析和设计。本文介绍了 CAN 总线技术基础、技术规范及 CAN 总线接口电气连接方式等内容,设计了基于 CAN 控制器 SJA1000 的智能控制系统的硬件电路及模块化软件。CAN 总线的采用,增强了弯管流量检测系统的开放性、提高了可靠性,并有灵活的通讯功能。本课题源于工程实际,作者对该系统做了大量的方案选择和测试实验。实验和实际工程应用表明,该系统结构合理、可靠性高、操作简便、性价比高,可以满足一般实际应用的要求。
【Abstract】 Field bus, make relationships between the process control devices andeven the high control management network, as a communication networkamong intelligent instruments in the field of process control automation,manufacturing automation. As CAN field bus is reliability, real time andagility in data communication, proposals a reliability solution at the presentfield control system to improve the communication among intelligentinstruments. After having analyzed elbow flowmeter technology development statusand trend, every part is designed in order to develop one intelligent flowmeasure instrument & system based on CAN bus with elbow flow sensor,conversion and calculate. Being based on elbow flowmeter measurement theory, the theory of freevortex and forced votex is introduced. After the excellence and shortcoming isanalyzed and compared, forced vortex and flow adjusting coefficient areselected in paper. And the elbow sensor with R/D=1.5 is designed. Using new MCU and computer hardware & software technology and fieldbus technology, put forward difference of presses, density of liquid anddiameter of pipe real time amending technology. At the same time calibrationtransform, auto- calibration, voltage monitoring and CAN communicationinterface are analyzed and designed. CAN bus basic technology is introduced. In allusion to CAN bustechnology characteristic, researched and analyzed technology criterion, framestructure and CAN bus interface electric connection mode. Hardware andsoftware of intelligent control system based on CAN bus controller, SJA1000are designed. Accordingly, precision of elbow flow measure instrument &system is improved, enhance system’s opening, reliability and communicationfunction. The research roots in practice engineering. For practice system, Lots ofprojects are selected and Lots of integration and test are done. By experimentsand actual appliance, it is indicated that the system has some advantages, such II<WP=6>as, reasonable structure, high reliability, simple operation and high ratio ofperformance to value.
【Key words】 CAN field bus; elbow flowmeter; microcomputer; flow coefficient; self-calibration;
- 【网络出版投稿人】 燕山大学 【网络出版年期】2004年 04期
- 【分类号】TH814
- 【被引频次】3
- 【下载频次】209