针对金属构件近表面存在的裂纹缺陷，基于远场涡流检测法，建立了包含运动扫查平台、信号激励、数据采 集等模块的远场涡流检测扫查系统。 运动扫查平台利用 PLC 控制步进电机带动三维扫查架运动；编写 LabVIEW 数据采集程序，控制 NI 采集卡对检测信号进行采集，在 LabVIEW 软件与 PLC 之间使用 MX 组件通讯，使 LabVIEW可以访问 PLC 的寄存器，读取三维扫查架各轴位移信息，软件与硬件相结合，实现缺陷的自动化检测。 设计了 2 种不同类型的缺陷，实验结果表明，随着缺陷埋深减少及缺陷宽度增大，得到的缺陷信号也在变大，实际缺陷位置与检测到的缺陷位置误差为 0.001 mm；同时，该方法能够检测出最大埋深为 5 mm、宽度为 0.2 mm 的矩形缺陷。

For crack defects near the surface of metal components, based on the far-field eddy current detection method, a far-field eddy current detection sweeping system that includes a motion sweeping platform, signal excitation, data acquisition and other modules is established. The motion sweep platform uses PLC to control the stepping motor to drive the three-dimensional sweep frame movement. A LabVIEW data acquisition program was written to control the NI acquisition card to collect the detection signal, and MX components were used to communicate between the LabVIEW software and PLC so that LabVIEW could access the PLC's registers to read the three-dimensional sweep frame displacement information of each axis. Automated detection of defects was achieved by combining software and hardware. Two different types of defects were designed. The experimental results show that with decreasing defect depth and increasing defect width, the obtained defect signal also increases, and the error between the actual defect position and the detected defect position is 0.001 mm; at the same time, the method is able to detect rectangular defects with a maximum depth of 5 mm and width of 0.2 mm, which proves the feasibility of the method.