一种基于加样针结构的电容法液位检测系统  

A liquid level detection system with capacitance method based on pipette structure

作　　者：杨溢[1] 郭阳宽[1] 祝连庆[1] 刘超[1] 孟晓辰[1] 

机构地区：[1]北京信息科技大学光电测试技术北京市重点实验室,北京100192

出　　处：《传感器与微系统》2015年第10期48-50,共3页Transducer and Microsystem Technologies

基　　金：北京市属高等学校创新团队建设与教师职业发展计划资助项目(IDHT20130518);长江学者和创新团队发展计划资助项目(IRT1212)

摘　　要：为实现全自动凝血分析仪加样过程高灵敏度和高精度的液位检测,采用了电容传感器原理和步进电机运动控制相结合的方法。介绍了探针式电容传感器的结构与工作原理;分析了电容/周期转换法的检测原理;组建了实验系统对灵敏度和测量精度进行检测。实验结果表明:加样针接触液面的瞬间,脉冲周期发生40%左右的显著变化,液位测量的标准差为4.1μm。To achieve high sensitivity and high precision liquid level detection on pipetting process of automatic coagulation analyzer,a capacitive sensor principle combined with stepper motor motion control method is used.Structure and working principle of probe-type capacitive sensor are introduced; detecting principle of C / T conversion method is analyzed; an experiment system is set up to test sensitivity and precision. Results show that the change of pulse period reach to around 40 % at the moment while pipette is contacting liquid surface,the standard deviation is 4. 1 μm.

关 键 词：液位检测 加样针 电容传感器 电容/周期转换法 

分 类 号：TH773[机械工程—仪器科学与技术]