Design Of Multichannel Ultrasonic Testing System Based On USB2.0

In five conventional non-destructive testing methods(including ultrasonic testing, rayinspection, eddy current testing, magnetic particle testing and leak detection), ultrasonicnondestructive testing technology has advantages of a wide range of application, fast speed,accurate defect location, low cost, high sensitivity, besides, it is easy to use, harmless tohuman body and convenient for on-site operation compared with other non-destructive testingtechnology.Currently, PCI or ISA interface is adopted in relatively mature ultrasonic detecting system,whose drawback lies its troublesome installation and it has poor scalability by the limitted slotnumber, address and interrupt resource of the computer. Relative to PCI or ISA interfaceadoptted in ultrasonic acquisition system, USB transmission interface can directly hot-plug,and it has strong scalability no subject to the limitted slot number, address and interruptresource. A variety of interfaces need not be used in the PC, ultrasonic flaw detection systemis a relatively independent whole to the PC, which helps to reduce the external inter ferences,and improve the reliability and portability of the system greatly. And so the system has a goodpractical application value and promotion prospects.Based on analysis of the defects of large-diameter thick wall pipe, three detectionmethods (the perpendicular incidence detection method, transverse wave slant method,longitudinal wave slant method) are chosen for defect detection in large diameter thick wallpipe, and USB2.0is chosen as acquisition system for communicating with the host computer.In the system, CY7C68013A of CYPRESS company is used as USB2.0interface chip tocommunicate with the upper computer, CPLD is used as the main processor to communicatewith CY7C68013A, which can generate a gating signal to choose a valid echo signal, co ntrolTLC5620to generate a gain signal, and control AD7891for acquisition from analog to digital.In the Keil development environment, programming of CY7C68013A is completed. In themaxplus II development environment, Verilog language is used to write program of CPLD. In Microsoft Visual Studio2012development environment, the C++language is used to developcontrol software of system and signal processing. The system can set the operating parametersof the4-channel ultrasonic flaw detector, read echo data in the buffer, process the ultrasonicecho signal to remove noise and interference signal, and plot detection result graphics.