In order to meet the requirements of high sampling rate and exactness in general mechanical vibration monitoring, a high precision data acquisition method of wireless sensor networks (WSNs) node is proposed based on IEPE accelerometer. A dual-core-processor architecture is adopted to reduce the coupling of network maintenance and acquisition control. Using independent high precision clock to control the acquisition timing, which improve data collection frequency accuracy. A scheme of low noise DC-DC power conversion is designed, which takes into full consideration of the conversion efficiency and thus controls the power supply noise rejection within 30μVRMS. The high precise constant current source with power supply noise self-rejection is designed, which reduces the signal noise of IEPE accelerometer. Furthermore, the steady passband ripple three-order low pass filter is designed for avoiding the frequency aliasing effectively and improving the data acquisition amplitude accuracy. Experimental results indicate that the signal noise is merely 40.7μVRMS and the average amplitude error within passband is merely 0.37%. In comparison with the data collection of wired system NI9234, the frequency error of WSNs is within the minimum frequency resolution, and the maximum amplitude error is merely 2.99%. Results verify the validity of the high precision data acquisition method of mechanical vibration wireless sensor networks node.
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