【作者】 马永成；

【导师】 莫德举；

【作者基本信息】 北京化工大学 ， 检测技术与自动化装置， 2005， 硕士

【摘要】 涡街变送器是20世纪70年代发展起来的一种新型流量仪表,由于它具有其它流量仪表不可兼得的优点,因而在市场中占有广阔的应用范围和发展空间。课题所研究的多变量涡街变送器是在传统涡街变送器的基础上开发的。它将温度、压力和流量传感器融为一体,通过对气体密度进行补偿,实现了精确的质量流量测量。同时,在设计中引入HART通信协议,使仪表具有了远程通讯的功能。 论文首先简要说明了多变量涡街变送器的组成原理和机械结构,并在现有气体密度补偿理论的基础上,提出了适合不同气体的密度补偿公式;然后详细介绍了变送器的软硬件设计,包括芯片选型、温度压力信号采集电路的设计、涡街信号放大器设计、D/A转换电路设计以及部分功能程序的流程设计等。此外,对软硬件设计时常用的一些抗干扰与降低功耗措施也进行了简单介绍;接着着重阐述了HART通信协议及其在变送器中的软硬件实现方法;最后,对整个系统进行了测试并获得较为满意的结果。 通过理论分析、实验验证,该变送器能较好的完成测量任务,测量结果准确,测量电路简单,系统功耗低,运行可靠。仪表与上位机的双向数字通讯正常,符合HART通信协议的规范要求,具有非常广阔的发展前景。更多还原

【Abstract】 Vortex transducer is a new type flowmeter that has developed from 1970’s. Because of excelling others in some aspects, it has a wide applied range and expansive developing in the market. Multi-variable vortex transducer was developed on the basis of conventional votex transducer. It integrated temperature and pressure sensor with vortex sensor, and it realized the accurate measurement of mass flow through the compensation of gas density. The HART protocol is introduced in designs, and the function of remote communication is realized.The composition principle and mechanical structure of multi-variable vortex transducer is briefly described at first, and the formulas of density compensation which fit for different gases are presented on the basis of latest theory of gas density compensation. Then, the hardware and software designs of transducer that include the selection of chips, the design of the temperature and pressure signal collection circuit, the design of the vortex signal amplifier, the desigh of D/A convertion circuit and the design of some program processes are introduced in details. Furthermore, some methods of anti-interference and low power consumption are presented. Next, study is focused on the HART protocol content and how to communicate according to this protocol. At last, the whole system is tested and the satisfying results are achieved.Through the theory analysis and experiment check, this transducer can accomplish the target. It has exact result, simple measured circuits,更多还原