井下测井仪器数据总线的研究与设计

Research and Design of Data Bus for Downhole Logging Tools

针对井下测井仪器数据总线的数据传输及测井需求提出并设计了一个新的高速井下测井仪器数据总线方案。该方案采用1路CAN总线完成下发命令及上传小数据量测井仪器的数据,采用1路RS-485总线完成上传大数据量测井仪器的数据。所设计的RS-485总线通过在发送端采用8B/10B码、接收端采用位同步恢复技术实现了在100m非屏蔽双绞线上10 Mbit/s的高速数据传输,误码率小于1.0×10-11。通过测试,该方案在实验环境下工作稳定、可靠。利用现有器件可实现在210℃的环境温度下连续工作4h。

In view of the existing downhole logging data bus and logging requirements, designed is a new high-speed downhole logging data bus. The scheme adopts a CAN bus and a RS-485 bus. The CAN bus is used to upload data of logging tool with small amount of data and download commands to the corresponding wellqogging tool, and the RS-485 bus only upload large data of logging tools with amount of data. The RS-485 bus can perform 10 Mbit/s high-speed data transmission along 100 m unshielded twisted pair with an error rate of 1.0 ×10^-11 by using 8B/ 10B code in the sender and bit synchronization technology in the receiver. Through a series of experiments, the scheme is stable, reliable, and may be used in the existing log devices to work in the ambient temperature of 210℃for at least 4 hours.