An Improved Approach to RS485-Based Long-Distance High Speed Telemetry for Industrial Sensor Data

Abstract

In industrial fields such as seismic explorations, RS485 is considered a workhorse interface standard, and it is the most widely used for serial interface found on sensors. However, long-distance transmission at high data throughput is one of the key features. An improved RS485-based high-speed remote transmission method is developed to implement the transmission of large amounts of data from distributed sensors. Based on the signal integrity analysis, the hardware interface designs including interface chips and impedance matching are determined by continuous square-wave pulse transmission. Then a self-defined protocol with the aid of FPGA hardware real-time processing is designed to make high-speed clock recovery and frame synchronizations. The 8b/10b encoded data streams are transmitted via a twisted-pair cable in the experiment. The experimental results indicate that the designed RS485 transceiver unit can drive the 220 meter twisted-pair lines at 20Mbps data speed with an error rate of 10-11.