A system of vibrating wire displacement sensor data acquisition designed base on the NB-IoT

Vibrating wire sensors are widely used in bridge monitoring, but most of their communication methods are wired or high-power wireless communication methods, which cannot adapt to field bridge monitoring tasks. Therefore, NB-IoT communication technology of the new generation Internet of Things is studied and applied to bridge communication system. As the control core of the system, ARM controller combines Excitation and Pickup Circuits to achieve data acquisition and processing of vibrating wire displacement sensor. Based on the low-voltage progressive frequency sweep mode, the excitation circuit outputs the excitation signal to trigger the forced vibration of the vibrating wire. Vibration frequency signal is collected by vibration picking circuit. Based on frequency and temperature data, quadratic polynomial fitting is used for displacement output fitting. Displacement data is uploaded to the cloud platform by NB-IoT to realize remote real-time monitoring. The test results show that the resolution of measured frequencies is 0.1Hz, and the resolution of displacement is about 0.001mm.the system can meet the design requirements of bridge construction data monitoring with high displacement measurement accuracy, simple communication network and stable data transmission.