Design Of Oil-water Measurement System Based On Capacitive Fringing Field Effect

Nowadays, the water content of oil-water mixture detector cannot fit for People's Daily lives.This dissertation introduce a measurement system based on capacitive fringing field effect and PCB technology was designed, consisting of self-designed detection probe.Given the shortcomings of current market-applied methods and instruments in oil-water measurement, a measurement system based on capacitive fringing field effect and PCB technology was designed, consisting of self-designed annular detection probe, capacitance detection circuit, embedded processor,RS485 communication module and other components. When measure the water content,because of the water's solubility is very low,the water and oil will appear stratification,Different oil water content affects the dielectric constant,so detection probe will get the change in capacitance .And the design of oil-water capacitance detection probe was optimized by finite element analysis software COMSOL and capacitive fringing field effect of the capacitor plate & PCB technology. Capacitance detection circuit was designed in using the up to 28-bit accuracy capacitance detection chip FDC2212 . The system control hardware utilized embedded processor STM32F407ZGT6 based on ARM-M4 kernel and ran ? COS-? real-time embedded multi-tasking operating system. RS485 communication module could be extended to other handheld communication devices.which detection error was less than 1% and sensitivity could be achieved in 3.3PF/%, given the oil-water ranged from 0 to 80%.The follow-up performance of the detection system could be improved through calibration and data compensation.