Cable-stayed Bridges Measuring System Based On Virtual Instrument

The working state of the cable is very important to cable-stayed bridges. It is necessary to measure the tension of the cable. Traditional method to measure of the tension the cable that are either dissatisfying on precision or expend too much monry can't keep on with the requirement of the reality. The technology of virtual instrument is a kind of new developing technology in measurement and controlling field. It has well solved this limitation. Utilize this technology to develop the measuring system is the purpose of this thesis. This thesis has recommended measuring the method. Through comparing these methods this thesis expounds one measuring systems. It is based on multi-functional data collecting card and Portable PC. The data acquisition part of this measuring system is controlled by a singlechip. Because of some shortcoming of the data acquisition in this measurement system, so we do some improvement in the data acquisition part.The main devices include AT89C51,AD1674,MAX232,74LS373 and 74LS00. Data acquision and data processing divided is the main characteristic of these two measuring systems. Data acquisition part only takes charge of the sample and A/D conversion of the analog signal,the results of the conversion send to PC. UI and the module of data processing are compiled by LabVIEW on PC,including serial port,UI,show of the wave and data storage. Normal RS232 protocol is used between data acquisition module and data processing modlue.