电磁探伤系统中FPGA同步采样系统设计

The Design of Synchronized FPGA Sampling System in Electromagnetic Defect Inspection System

在线钢轨探伤中,需要在高速情况下同步实现电磁投影激励和弱磁信号检测。针对目前多路数据同步采集系统的局限,以Virtex-5系列的FPGA为核心控制模块,应用AD7760∑-△型模数转换芯片实现了精度为24位、最大采样速率高达20M的高速同步采集系统。给出了多路同步采集系统的实现框架及原理,针对目前高速数据采集系统存在的采集和速度、资源利用不合理以及硬件成本较高等问题,给出了一种同步采集的方法。实验表明,该方法实现了多通道,高分辨率并行高速A/D同步采集的有效控制,满足了在线钢轨探伤系统对高速情况下,实现同步电磁投影激励和弱磁信号检测的要求。

In online rail flaw detection,we need the synchronal detection of electromagnetic projection incentives and weak magnetic signal in high speed condition.Due to the limitations of the current multi-channel synchronal data acquisition system,we chosed Virtex-5 family of FPGA as the core control module,used the AD7760 ∑-Δanalog to digital converter chip to achieve the accuracy with 24 bit,the maximum sampling rate was up to 20M synchronous acquisition system.This paper presented a multi-channel high-speed synchronous acquisition system architecture and control theory,analyzed the status of the data acquisition system in the current.Aiming at the unreasonable problems of acquisition and transmission speed,resource utilization,and the high cost in high-speed data acquisition system,we proposed a synchronal acquisition method.The realization results showed that the method realizes multi-channel,high-resolution,parallel A/D synchronal acquisition,meets the demand of the synchronal detection of electromagnetic projection incentives and weak magnetic signal in high-speed case.