基于AD7612的高精度电压检测技术及实现

在石油测井中,地层水电阻率和阳离子交换量与电化学测井参数极化率和自然电位之间的关系可为砂泥岩储层评价和水淹层问题提供一条有效的途径。为了高精度快速测量极化率和自然电位,设计了一种基于DSP和AD7612的高精度电压检测技术及其实现方法。根据当前采样信号的特点,重点阐述了提高测量精度的方法：电压多次采集取优、四通道放大倍数的校正、四通道数据的合理取优、AD采样电压分段自校准、AD零漂校正。并通过相应的硬件实验测得了校正前后的实验数据,证实了该设计的有效性。

High-precision voltage detection based on AD7612

The relationship between formation water resistivity,cation exchange capacity and the electrochemical polarizability,spontaneous potential is very important to evaluate sand mud reservoir and water-flooded layer in petroleum well logging.For the purpose of measuring polarization and the spontaneous potential accurately,This paper introduces a way of high precision voltage detection and its implementation based on AD7612 and DSP.In addition this paper focuses on the ways of improving the measurement accuracy based on the characteristics of sampled signals： Voltage repeatedly collected,Four-channel magnification correction,Obtain the best result of four-channel data,AD sampling voltage sub-self-calibration,AD zero shill rectifying.Meanwhile this paper shows some corresponding experimental results which confirm the effectiveness of the design.