The Rearch And Produce Of The Scaning Control And The Data Acquisition System Applied To Dual-Energy X-ray Absorptiometry Instrument

The bone density survey is an important device for judging wether the ossein is lost and diagnosising osteoporosis. This article first introduces prestent situation of the development of the bone density measuring technique and the method of bone density measuring.Then introduce the research and produce of the scaning control and the data acquisition system applied to Dual-Energy X-ray absorptiometry instrument.The scanning control and the data acquisition system are essential parts of Dual-Energy X-ray absorptiometry instrument.The developing work of the whole design is to choose C8051F020 MCU as a master control and to complete the related program development of each blocking circuit such as gathering, scanning, controling and so on.The design is as follows: MCU timer T2 is the standard timer of the two channel pulse counter of the item design. Fixed timer T0 and timer T4 serve as high energy and low energy counter seperatedly. Stepping motor of the X-ray source and the detector are driven by MS-3H090M driver. The data btween MCU and PC machine are transmitted through the serial port; The man-machine interaction operation contact surface is completed by Visual C++.The experiment shows that when the count rate is more than 1M, and the length of the single-channel scan is 30cm the testing time is 120s,and the time of the double-channel scan is less than 300s. The result demonstrates that the data acquisition and the scanning control system meet the requirements of the design.