Design and Realization of Modbus Protocol Based on Embedded Linux System

With the rapid development of the embedded computer technology, the new generation of industrial automation data acquisition and monitoring system, which takes the high performance of embedded microprocessor as its core, adapts well to the application system. It meets the strict requests of the function, reliability, cost, size and power consumption, etc. In the industrial automation application system, the Modbus communication protocol is widespread industrial standard and is used in massive industrial equipments, including DCS, PLC, RTU and the intelligent instrument, etc. In order to reach the demand of the embedded data acquisition monitoring system of the industrial automation application, an embedded data acquisition monitoring platform based on Modbus protocol under the Linux environment is designed in this paper. The serial port Modbus master protocol is realized, which includes two kinds of communication mode: ASCII and RTU. As a result, communicating with various serial Modbus salve protocol equipments can be satisfied. The Modbus master realized by this embedded platform is stable and reliable. It has excellent prospect in the embedded data acquisition monitoring system of new automation applications.