A New Design For NDT Device

In this article, the study of a new NDT-device based on magnetostrictive effect is expatiated in detailed, and it can realize the NDT of all kinds of steel pipe. The microchip W78E58B of Winbond Co. is adopted as MCU in this device. It includes two important parts such as the system of exciting and receiving. The function of the exciting-part in the device is transmitting one to eight pulses which frequency is 5Khz to 250Khz. The voltage of the pulse is alterable from five chances (200V,400V,600V,800V,1000V). In this paper, a new high voltage transmitting circuit is given combining with microchip and high frequency circuit design technology. It can improve transmitted and received obviously, then enhance the measuring precision and anti-jamming capability. The receiving-part must detect a very weak signal with much stronger disturbing signal. I select the Integrated-Filter(MAX275) made from MAXIM to filter and magnify the signal, and then collect the signal with the Data- Acquisition-Card (DSO-220 USB) and transmit to computer via USB. In addition, the data is transmitted to computer by an isolated RS-232 interface, and computer can read Detecting-Data and modify the parameter of the pulse. The paper describes the design course of the device in chapter: chapter 1 describes the theory and history of NDT, the layout of instrument is given in chapter2, and then describe the design of software and hardware of the device in detail, chapter 6 and 7 introduces the serial communication protocol and the instrument, the last chapter is the summarize.