According to the requirement of national information security, a cable detector based on Loongson 2H is designed. The cable detector consists of CPU processing unit, FPGA logic control unit, conductive resistance detection circuit and insulation resistance detection circuit. CPU processing unit processor uses domestic Loongson 2H chip, which has strong expansion ability and provides common external interface. The FPGA logic control unit mainly realizes the control of the interface, the digital acquisition signal processing and the communication of CPU processing unit. The conductivity detection circuit adopts the Kelvin 4 wires method to effectively eliminate the impedance at both ends of the test line and improve the measurement accuracy. The insulation resistance is measured by the method of partial pressure, and the high voltage dc voltage is reduced and then transferred to FPGA after AD conversion. With the method of transfer switch reuse, reduce the number of the relay, reduces the equipment cost and volume, reduce the power consumption of the engine, and increases the life span of the equipment and the safety of the measurement site. The application results show that the cable detector based on Loongson 2H is practical and has good application value.%针对国家信息安全的需求,设计一种基于龙芯2H 的电缆检测仪.电缆检测仪由 CPU 处理单元、FPGA逻辑控制单元、导通电阻检测电路、绝缘电阻检测电路组成.CPU 处理单元处理器采用国产龙芯2H 芯片,扩展能力强,可提供常用的外部接口;FPGA逻辑控制单元主要完成接口端的控制、数字采集信号处理和CPU处理单元的通信;导通电阻检测电路采用开尔文四线检测法,有效消除测试线正负两端的阻抗,提高测量精度;绝缘电阻采用分压法测量,将高压直流电压降压后,再经 AD 转换后至 FPGA 处理.采用通道切换开关复用的方式,减少了继电器的数量,降低了设备成本和体积,减少了整机功耗,增加了设备使用的寿命及测量现场的安全性.实际结果证明:基于龙芯2H的电缆检测仪切实可行,有很好的应用价值.
展开▼
