Design the Network Bus of Logging Downhole Tools on 10BASE-T1S Network

With the advancement of array and imaging logging technologies, it has become necessary to develop a downhole tools bus that occupies fewer signal lines and offers high communication rates. This paper presents the hardware design of a new networked industrial bus for logging downhole tools that utilizes a single pair of twisted pairs as the communication medium. The bus architecture meets the multi-node adaptive ability and offers a transmission rate of 10 Mbps. To design the network bus of logging downhole tools, the 10BASE-T1S Ethernet PHY device with RMII interface and the 10BASE-T1S Ethernet PHY + MAC device with SPI interface are used, both of which utilize the lightweight and open source TCP/IP stack LwIP. The networked downhole tools bus successfully connects conventional grand slam logging tools and meets the technical requirements of imaging logging tools such as array acoustic logging tools, array induction logging tools, and acoustic electric imaging logging tools. The scheduling scheme utilized in this design includes a physical layer conflict avoidance (PLCA) mechanism, which ensures fairness of transmission opportunities in the system by avoiding bus conflicts and retransmissions, thereby reducing the available bandwidth limit. This paper presents a novel approach to Ethernet data transmission through single pair of twisted pair cables, significantly reducing the occupation of signal lines.