Eddy current testing employs rich frequency sinusoidal signal as the excitation source, and many frequency components are included in corresponding response. Meanwhile, the counter-interference of eddy current testing is improved. An eddy current testing system suitable for on-line detection is developed based on current testing, data acquisition and virtual instrument. The system was composed of eddy current testing hardware circuit, PXI bus system and relative software. The hardware circuit generates excitation signals with excellent waveform, stable frequency (range of 0～5MHz) and stable amplitude. Combining with PXI bus system and LabVIEW virtual instrument software platform, the system offers functions of acquisition, analysis, processing and display of the signals. Testing experiments were done through the system, and the results showed that the system can detect the defect diameter of 0.6mm, with a good testing capability.%涡流检测技术采用频谱丰富的正弦信号作为激励源,响应中包含多个频率成分,增强了涡流检测的抗干扰能力.将涡流检测技术、数据采集技术与虚拟仪器技术有机结合起来,开发了适用于在线检测的涡流检测系统.系统由脉冲涡流检测硬件电路、PXI总线系统以及相关软件组成.硬件电路可产生性能良好,频率、幅值稳定的激励信号,频率范围为0～5 MHz;结合PXI总线系统和LabVIEW虚拟仪器软件平台,实现了信号的采集、分析、处理与显示.实验结果表明,本系统可以检测直径为0.6 mm的缺陷,具有较好的量化检测能力.
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