平面电容传感器液位检测系统设计

为了对高度小于100mm的液位进行非接触式测量，采用液位变化改变平面电容边缘电场参量的方法，对平面电容传感器的工作原理进行了理论分析，研究了平面电容传感器的结构参量对其灵敏度、穿透深度的影响，并对传感器结构参量进行了优化, 基于平面电容传感器, 设计了非接触式低液位检测系统，通过对纯净水、洗洁精溶液和墨汁的实验验证，取得了0mm~100mm范围的液位测量数据。结果表明，该检测系统工作稳定，具有线性输出，重复性误差约为±0.28%，数据修正前的测量误差小于7.8%。这一结果对非接触式较低液位的检测是有帮助的。

Design of liquid level detection system based on planar capacitive sensor

In order to implement non-contact detection for liquid level less than 100mm in height, the method for changing planar capacitive edge electric field parameters by liquid level was adopted. The working principle of planar capacitive sensor was analyzed, and the effect of planar capacitive sensor structure parameters on sensitivity and penetration depth was studied. The method of structural optimization design on sensors was proposed. The non-contact detection system for lower liquid level was designed based on planar capacitive sensors. The measured data of pure water, detergent solution and ink within 100mm was obtained by experimental verification. The experimental results show that the system with linear output is stable. The repeatability error is about ±0.28%, and the measurement error is within 7.8% before data correction. The results are helpful for non-contact detection for lower liquid level.