RS-485 bus-based high-speed data/power transmission method for seismic exploration instruments

An RS-485 bus-based high-speed serial data transmission system was developed for high-speed remote long wire transmission of a large amount of data collected by seismic exploration instruments using FPGA technology. The system structure and communication protocols are given. The power in the Ethernet is used to drive the RS-485 bus with transmission of the 48 V DC and data signals via the same twisted-pair electric cable. The rising/falling edges of the serial signals are used as the start symbols for high-speed clock sampling to enable bit synchronization time-clock recovery and data frame recognition with the 8 B/10 B encoded mode. The sampling clock frequency is 10 times higher than the sending clock signal. Data transmission experiments show that the system provides remote data transmission along a 220 m twisted-pair cable at transmission rates of up to 20 Mb/s with an error rate of 10^-11.