基于USB总线的远探测方位反射声波成像测井仪数据读取接口设计

Design of Data Reading Interface for the Borehole Azimuth AcousticReflection Imaging Tool Based on USB Bus

远探测方位反射声波成像测井仪(BAR)是新一代成像测井仪,其测井数据存储于内部大容量存储模块中;为了实现在测井现场快速读取和回放测井数据,设计了一种基于USB总线的数据读取接口;数据读取接口通过USB总线与PC通讯,通过自定义高速串行总线与下井仪数据存储模块通讯;高速串行总线为基于M-LVDS的差分总线,设计的工作频率为80 MHz,采用8B/10B编码;数据读取接口电路采用FPGA作为主控芯片,高速总线协议和传输控制均在FGPA中实现;所设计数据读取接口已实现8口井的现场测井数据读取,数据读取速度达到57 Mbps;该设计实现了测井数据的现场快速读取和回放,保证了测井数据检验的时效及测井施工的效率。

The borehole azimuth acoustic reflection imaging tool(BAR)is a new generation of imaging logging tool,and its logging data,which can’t be transmitted to ground for shortage of telecom rate,is stored in an internal mass storage module.In order to realize timely reading and replay logging data infield,a data reading interface based on USB bus is designed.The data reading interface communicates with the PC through the USB bus,and communicates with the down hole data storage module through a custom high-speed serial bus.The high-speed serial bus is a differential bus based on M-LVDS.The designed frequency of the bus is 80 MHz and 8B/10B encoding is employed.The data reading interface uses FPGA as the main control chip,which implement the high speed bus protocol and transmission control.The data reading interface has tested in field,and the data reading rate reaches 57 Mbps.The design realizes the fast reading and replay of logging data,which ensures the timeliness of logging data inspection and the efficiency of logging operation.