11 July 2009 Measurement of grain moisture with a coplanar electrode capacitance probe
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Proceedings Volume 7490, PIAGENG 2009: Intelligent Information, Control, and Communication Technology for Agricultural Engineering; 74901D (2009); doi: 10.1117/12.837325
Event: International Conference on Photonics and Image in Agriculture Engineering (PIAGENG 2009), 2009, Zhangjiajie, China
Abstract
A coplanar electrode capacitance probe which can work on hostile environments has been used to measure the grain moisture. An active shield electrode can block the electric field from out of the sense area and decrease the stray capacitance of the sensor, thus increasing the sensitivity of the sensor. Finite element method has been used to analysis the effect of the active shield electrode. The measuring principle is based on an oscillator working at approximately 2 MHz. The dielectric property of the grain between driven electrode and sensing electrode affects the frequency of the oscillator. According to the measuring experiment, a sensor has been designed whose accurate is 0.5%.
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Liu Yang, Yu Tan, Lan-lan Dong, Zhi-huai Mao, "Measurement of grain moisture with a coplanar electrode capacitance probe", Proc. SPIE 7490, PIAGENG 2009: Intelligent Information, Control, and Communication Technology for Agricultural Engineering, 74901D (11 July 2009); doi: 10.1117/12.837325; http://dx.doi.org/10.1117/12.837325
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KEYWORDS
Electrodes

Capacitance

Sensors

Dielectrics

Oscillators

Capacitors

Electric field sensors

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