The Design Of Intelligent Controller Based On Industrial Ethernet

Ethernet has become a new hot spot in industrial control network area in recent years. With the development of Ethernet, some problems in communications, such as accuracy, timeliness, stability, reliability and so on, are solved. EPA protocol, which was promoted by China, was listed formally as class 14 of international standard of field bus IEC 61158.Intelligent controller is an essential part of EPA control system, and its design and implementation are the main content in this paper.First of all, combining the features and demands of the Ethernet and industrial con-trol network communications, this paper analyzes the feasibility of Ethernet applied in industrial control, as well as the strengths of Ethernet comparing with field bus. Besides, the development of field bus and industrial Ethernet are also introduced. The key techniques involved in the design and implementation of the field controller are studied, including the structure of EPA industrial Ethernet system, TCP/IP protocol groups, the features of embedded system, and the real time operate systemμC/OS-Ⅱ.Secondly, the design of intelligent controller is promoted combining the analyses of key techniques and the features of field controller. The main functions of field contr-oller include controlling and communicating, and the paper focus on the latter. The main function of intelligent controller is to realize the collection and operation for data, and then communicate with upper and lower network layer through Ethernet communi-cation interface. The communications with lower network layer is to control the inform-ation and to distribute and received the measurement data. The communications with upper network layer is to receive the configuration information from monitor layer and the control commands, and send the information data to the host computer for display and update to achieve the remote monitoring. Furthermore, CAN and RS232 the two communication interfaces are added to communicate with field devices for different communication interfaces.Then, the detailed design and implementation of software and hardware of intelli-gent controller are completed. The core chip of the field controller is 32-bits ARM micr-ocontroller LM3S8962 which is based on core Cortex-M3. The design of peripheral interface circuits is the main part of the hardware, including power block, digital I/O block, analog input blocks, Ethernet interface, CAN interface, RS232 interface and JT-AG interface. Designs of software include collection and operation of signals, implem-entation of EPA protocol. Lastly, system overall debug is done and the errors and defau-lts are summarized and analyzed.