Design Of Vibrating Wire Sensor Signal Acquisition Instrument

Since the reform and opening up, China’s economy has achieved the rapid development, and the engineering constructions have made the remarkable achievements. However, in order to ensure the rapid development of infrastructure, and as well as the safety during the production, China needs to continue to improve and perfect safety monitoring technology in the engineering field. In current engineering, vibrating wire sensors are used to measure the pressure, stress, osmotic pressure, sedimentation, tension and some other data related to system’s security. The signal acquisition instrument of the vibrating wire sensor,which is mainly used to collect vibrating wire sensor’s output signal, is a strong guarantee to promote the field of construction’s safety in production. This article developed a kind of new vibrating wire sensor signal acquisition instrument based on STM32Micro Control Unit(MCU), the collection instrument can directly capture real-time sensor data, and communicate with the computer, and finally achieve effective real-time monitoring of each monitoring point.This paper, by improving sensor excitation circuit and software program, achieved the adaptive sweep exciting and reduced the complexity of the circuits and circuit size. In frequency measurement, we make full use of the STM32chip resources, and finally achieved the precision frequency measurement and improved the measurement accuracy of the frequency signal. In circuit design, we have designed a pick-up of small-signal amplifier circuit. We added a band-pass filter circuit to the circuit in order to filter out the noise and improve the measurement accuracy of the signal.Vibrating wire signal acquisition instrument consists of two parts:the main control module and the measurement module. The main control module is used to set the sensor acquisition parameters and issue the sensor acquisition instruction to the measurement module. Measurement module measures the sensor output signal and sends the measured data to the master module. Master module hardware includes the smallest single-chip system, the power supply circuit, the voltage monitoring circuit, keyboard circuit, RS-485circuit, data storage circuit, the clock reset circuit and etc.. Measurement module hardware includes the smallest single-chip system, the power supply circuit, RS-485transceiver circuit, AD conversion circuit, isolate the excitation circuit and pick-up circuit. The software part mainly introduces the main control module of the operating procedures, sending acquisition command procedures, voltage monitoring procedures of the system, the SD card monitoring procedures, measurement module crash fixing and storing data files procedures. The measurement module software section describes the module initialization procedure, adaptive exciting program, and equal precision frequency measurement procedures. The article also highlights a self-customed RS-485communication protocol.which can achieve reliable communication of the main control module with four measurement module.Finally, we give software simulation under the analog circuits PSpice of the system. Software simulation can improve the reliability of the circuit design, and it can fully verify the circuit parameters to ensure the accuracy and reliability of the circuit design. In this paper, the tester measured the acquisition vibrating wire piezometer measurement data, and then the tester meet the demand for engineering applications based on the analysis of the data.