The Research And Application Of EPA Network Access Technology

EPA technology, one of the industrial Ethernet technologies, defines a deterministic scheduling management interface between the data link layer and network layer of communication in order to handle messaging to ensure the certainty and the instantaneity of communication., It does not change the structure of the Ethernet.With the advance and application of EPA technology, more and more devices need to be connected to EPA network. EPA communications switching equipment links the user equipment and the EPA network nodes to achieve transmission between user information and the EPA networks. The technology is defined as EPA communications network access technology, namely, the EPA-NAT (Network Access Technology).Based on the study and classification of the EPA Industrial Ethernet and EPA standard protocols, This issue analyzed the concepts and classification of EPA-NAT, emphasis on the EPA site I / 0 devices Access Technology, developed based on ARM development board and the EPA Communication Card's communications software, set up the actual EPA application system. After the whole system debug, validation of the EPA network superiority.This dissertation have finished the following works:⑴Discusses the development and current situation of industrial ethernet technologies, control system and EPA technology in datial, and EPA ethernet access technology has been studied and classified.⑵the Paper selected the access methods of field device, Identified the EPA adapter, and user access module (ARM9 development board) in field access device, set up the communication software and specific applications of EPA-NAT from the whole.⑶The EPA communication system established by topic, divided into three parts,are: ARM host communications, EPA communications card and the host PC, and ARM communications,PC in Control layer communications. Articles in this three-part hardware connection and software communications was analyzed and discussed in detail;⑷Describes the designing of the EPA specific application system to ARM9 development board as the core,and discusses the software designing of signal acquisition and processing module;⑸Set up a test system of EPA access equipment, including local communications test and PC configuration testing.in the EPA configuration software, author prepared XDDL device description file, carried out Configuration and the message was send and receive certification on EPA site equipment. Use of two EPA communication card which representative on-site equipments, In the PC, to test equipment configuration, had been achieved a number of equipment configurations.The test results show that the communication system for the EPA's communications software development and construction of specific applications are successful. Just after this set of communications software appropriate changes, it can be used for other users host based the SPI communication, Greatly reducing the EPA device development cycle for other host, Accelerate the dissemination of the EPA Industrial Ethernet applications.