摘要
提出了一种基于电容数字转换器(CDC)技术和虚拟仪器检测方法,设计了一种基于PCB技术的叉指电容液体物质检测传感器,并以此为基础研制了液态物质相对介电常数测定仪器。仪器采用的CDC芯片为AD7745,虚拟仪器数据采集卡为USB6008,设计实现了AD7745芯片宽范围电容检测的硬件电路。通过对几种液态物质相对介电常数的检测结果来看,仪器具有较好的检测准确性和重复性。
A new method based on capacitance-to-digital converter（CDC） and virtual instrument was put forward.A type of interdigitated comb capacitor sensor suitable for liquid sample measurement was designed by printed circuit board（PCB） technology.Based on the new method and sensor,a new liquid sample relative dielectric constant measurement instrument was designed.In the design,the CDC chip AD7745 and data acquirement hardware USB6008 were adopted.Especially,circuit designed for extended measurement range of AD7745 was accomplished.Some samples were tested on this instrument and the results show that the accuracy and repeatability are satisfactory.
出处
《化工自动化及仪表》
CAS
北大核心
2010年第7期62-65,69,共5页
Control and Instruments in Chemical Industry
