Research On Ultrasonic Testing System Based On PCI Bus

In order to realize digital, intelligentzed, image-oriented and automated of ultrasonic testing, a kind of ultrasonic testing virtual instrument system was developed by mines of rich hardware and software resource of PC, and technologies of ultrasonic testing,virtual instrument,Electronics,computer,PCI bus and signal processing technology, it is very meaningful to improve reliability,accuracy,efficiency and cost-effective of ultrasonic testing.In hardware development, non-resonant ultrasonic transmit circuit was designed by DC-DC high-voltage module giving the capacitor charging and transient discharging producting negative high-voltage which incented ultrasonic probe sending corresponding frequency ultrasonic.It improved the flexibility and ensured the veracity of ultrasonic frequency. Ultrasonic receive circuit mainly included amplifier circuit with adjustable gain, filter circuit and detection circuit. The amplifier circuit used two AD602 to amplify the signal for 4 times. The gain could change from -40dB to 120dB; The filter circuit took use of RLC circuit with good filter effect and no distortion; The detection circuit achieved positive, negative and bi-directional detection of ultrasonic signals, which had good effect on high frequency noise suppression by using LM733 as a full-wave rectifiers with high common mode rejection ratio. The high-speed data acquisition card based on PCI bus was designed in order to realize high-speed acquisition. The data acquisition circuit used AD9057 chip with sampling frequency for 40MHZ and sample precision for 8 bit; The logic control program of FPGA used VHDL language which realized the logic control of ultrasonic data acquisition and transmission; The PCI9052 interface chip achieved high-speed data transmission to the PCI bus, which could simply PCI bus protocol and reduced the development cycle.of PCI bus.In software development, PC software for ultrasonic inspection system with friendly interface was developed by NI LabWindows / CVI and the driver was developed by NI-VISA. In order to improve the signal to noise ratio, wavelet analysis was applied to denoise and improved the signal to noise ratio of ultrasonic signal. The expenriment results show that the system achieves ultrasonic testing, has high testing precision and achieves digita of ultrasonic testing, which makes a good foundation for ultrasonic testing with images, intelligence, automation, as well as the quantitative and qualitative analysis of defects.