A low-power vibrating wire sensor and its excitation detection method

Abstract

The invention discloses a vibrating wire sensor with low power consumption, which includes a vibrating wire, a coil, a sensor housing, an excitation circuit unit, a vibration pickup circuit unit and a main control unit; the main control unit includes a pre-vibration module, a re-vibration module, a frequency detection Module and signal processing module, the signal processing module records the effective re-vibration frequency signal, and at the same time controls the excitation detection process of the sensor, so that the sensor works in two modes of steady state and unsteady state, and according to the recorded effective re-vibration frequency value, Calculate the excitation frequency value output by the re-vibration module in the steady-state working mode. The invention provides a vibrating wire sensor with low power consumption, which changes the excitation mode of the vibrating wire, changes the traditional low-voltage sweep frequency excitation mode into the excitation mode of pre-vibration combined with re-vibration, and detects the frequency during pre-vibration The value is used as the excitation pulse frequency for re-vibration, thus achieving the effect of energy saving.

Description

technical field [0001] The invention belongs to the technical field of sensors, in particular to a vibrating wire sensor used for displacement or deformation measurement of structures. Background technique [0002] In the daily maintenance of large structures, it is very important to measure the deformation or displacement of its key components. The stress magnitude and distribution changes of the above-mentioned stressed components most directly reflect the health of the structure. Therefore, the stress status monitoring of these components And the safety analysis and evaluation based on this is of great significance. [0003] At present, the sensitive element of the vibrating wire sensor is a metal wire string, which is connected and fixed with the force-bearing part of the sensor. Various physical quantities are measured by using the relationship between the natural frequency of the steel string and the applied tension on the steel string. The vibrating wire sensor It is...

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Problems solved by technology

[0005] However, since the frequency sweep signal is a continuous pulse signal from the lower frequency limit to the upper frequency limit, in order to ensure the excitation effect, the pulse of each frequency must last for several cycles, and the excitation time is too long, resulting in high energy consumption, which limits the sensor In the application of remote unattended measurement system, in order to improve the battery life and save energy consumption, the electric excitation method of the vibrating wire sensor must be improved

[0006] In the "Journal of Sensor Technology", Volume 23, Issue 1, 2010, the article "Optimization of Vibrating Wire Sensor Vibration Strategy" discloses a vibrating wire sensor frequency detection scheme that combines initial measurement and retesting. The method first obtains an initial value of the vibration frequency, and then performs a second low-voltage string excitation with the initial value to obtain an accurate value. Although this program can obtain high measurement accuracy, it needs to be carried out twice each time. Encouragement and detection, the energy consumption is still high, so it is difficult to adapt to the unattended detection requirements in the field such as bridges in a slowly changing state

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