【作者】 陈力；

【导师】 陈仁文；

【作者基本信息】 南京航空航天大学 ， 测试计量技术及仪器， 2006， 硕士

【摘要】 近年来,伴随着工业生产、医疗卫生等领域的技术进步,人们对流量计量提出了更高的要求,而在全球自然资源供应日趋紧张的今天,提高流量测量精度更具有举足轻重的现实意义。本文以一种新型的差压式流量计——纺锤体流量计作为流量测量前端,结合嵌入式技术和RS-485串行通信技术,共同构成智能化流量积算控制仪系统。本着小型化、智能化的原则,该积算仪采用SST公司的微控制器SST89E564RD作为控制核心,并设计了由数码管和矩阵式键盘组成的人机对话接口。在测量过程中,系统以流量计节流所获得的差压信号作为主信号、绝压和温度信号作为补偿信号进行流量积算,这三种信号分别由相应传感器感知后,经各自的物理信号测量电路转换为电信号,再由A/D转换模块转变为数字量,交微控制器进行处理、积算。置于测量现场的多台积算仪与上位PC机之间可以通过RS-485串行总线进行数据传输,构成高精度的分布式测量网络。采用纺锤体流量计作为测量前端,成功的解决了传统节流装置测量精度低、压力损失大等缺陷,配以专用的积算仪系统,不仅避免了通用变送器与通用积算仪之间多次A/D、D/A转换所造成的精度损失,提高了测量精度,还简化了系统结构,使仪表的安装更加方便,具有很高的实用价值。更多还原

【Abstract】 In recent years, people have paid much more attention to the accuracy of flow measurement as technology progresses.The intelligent flow totalizer system in this design is combined with the spindle flowmeter, the embedded system techniques and serial communication techniques. Spindle flowmeter, a new type of differential pressure flowmeter, is used as the sensor of flow measurement. And aiming for a small and intelligent design, we use the MCU named SST89E564RD as the main controller, the LEDs and the keyboard as the user interface. During the period of measurement, the transduction circuits transform the differential pressures, the absolute pressures and the temperatures received by the sensors into the voltage signals, and then, the voltage signals are transformed into digital signals by the A/D convertor. The MCU processes these digital signals and calculates the cumulation of the flow. Finally the totalizers contact with the PC by RS-485 bus to form a distributed measuring network.The spindle flowmeter and the especially designed totalizer highly improve the precision of measurement, and the measuring system made up of them is very easy to use.更多还原