Desigen And Research On Industrial Ethernet Communication Adapter Based On Modbus/TCP Protocol

During the rapid construction period of smart grid and wisdom city, it raises higherrequirements to automation level of industry; the key to solve the problem is to buildunified communications network and protocol. Fieldbus network and protocol widely usedalready can’t meet the requirements in the compatibility aspect and communication distanceand speed aspect, the rapid development of Ethernet technology raises a new opportunity tosolve the problem, we can learn from advantages of fieldbus to solve the key problem ofEthernet, Ethernet technology learn from fieldbus’s strengths to offset its weakness,finally it unified to industrial Ethernet gradually, this represents the latest developmentdirection in the field of industrial control.Modbus/TCP Platform is one of the prominent representatives of the integration offieldbus and industrial Ethernet; there are broad prospects for development. This paper iscommitted to solve the problems of interconnection and communication that is between theModbus serial bus and Modbus/TCP industrial network. And it designed and developed aremote control gateway base on Modbus/TCP protocol.Firstly, this paper discussed the research background and meaning, then it introducedthe research status at home and abroad and the key technology to implement industrialEthernet communication adapter based on Modbus/TCP protocol; it also conductedresearch on architecture and communication mechanism of these two kinds of protocol.This part provide theoretical basis for the follow-up works.Secondly, this paper designed supporting hardware and core software of thiscommunication adapter used modular design thought based on above theoretical study. Thehardware selected16-bit single chip of Freescale as the core, it designed MCU modulecircuit, power drive circuit, EIA-485serial port drive circuit, Ethernet interface drive circuit,reset and crystal resonance circuit, communication status indication circuit; The softwareselected VC++as development platform and Codewarrior5.1as develop platform, itdesigned OpenTCP protocol stack module, Ethernet and Modbus serials portcommunication module, communication parameter configuration module. It can realizeinterconnection and interflow between Modbus and Ethernet through the cooperation ofsoftware and hardware. Finally, this paper adopted simulation test and joint test to validate this adapterfunction well, it simulated actual working environment and set up test system with multiplecommunication nodes at joint test situation, it also captured waveform of communicationsignal used oscilloscope provided by Tianjin electronic instrument measurement center tovalidate the function of this adapter, it provided test results with traceability andimproved the credibility of the test results.