Distributed Bridge Health Monitoring Data Collection And Transmission System And Its Key Technologies

In recent years, bridge safety incidents occurred frequently. Various bridges collapse causes a large number of casualties and property loses, therefore, people pay more and more attention to bridge monitorning, but most health monitoring of bridges in our country is still mainly at the stage of manual testing, however, this method can't meet the needs of modern bridge health monitoring. Fortunately, along with the development of measurement technology, the bridges can be monitored automatically by virtual instruments.This dissertation is mainly concerned about how to achieve bridge health auto-monitoring. After analysis and comparison of various bus technologies, this dissertation chose PXI measurement instruments of NI Corporation to consist the hardware of the data acquisition system.In the bridge health monitoring system, the acceleration signal reflects the damage of the bridge at the moment when it suffering a collision or earthquake. Therefore, all signals of accelerometer should be acquired synchronously in order to reflect the health state of the bridge accurately. This dissertation particular introduce the characteristics of PXI-4472B and discuss the synchronously conditions between many different DAQ cards because this project select it to acquire signals of acceleration. Jinsha River bridge monitoring system is based on distributed monitoring structure, so every data acquisition units have to share many signals just like oversample clock etc. for the sake of synchronous acquisition. This dissertation posed a method which used CPLD chips to drive fiber transceiver to route all necessary signals to actualize synchronous acquisitions.The software is the core part of Virtual Instrument. First, this dissertation analysis the software requirements of this project, then the software is divided into five main parts: Data acquisition, Data processing, Data storage, Data communication and user management. After the completion of mission analysis, this dissertation selected LabVIEW as the program language because of its high efficiency and powerful functions to complete the tasks of all parts. The software programming was focused on data storage, as well as the realization of data transmission. LabVIEW realize classification of data storage and user's database management in the project primarily through the operation of Microsoft Access database. This system must have the ability to exchange data efficiently and safely between acquisition modules and control center, so Datasocket technology is chosen as the communication protocol. And then, this dissertation designed a friendly interface, users use it can access the history data, real-time data and the result of the data process. At last, this dissertation summarize a number of experience on the Virtual Instrument's development, it also can be used for reference field.