The Research On Real-Time And Synchronous Control Network Over Ethernet

Ethernet has been widely accepted in information domain. It is possible to use Ethernet in industrial control systems. Industrial Ethernet is a kind of field bus technology which applies Ethernet in industrial field environment. Ethernet must be improved in order to meet the requirements of industrial control systems. It has many merits such as low installation cost, high communication speed, supporting variable services and large customer quantity. However Industrial Ethernet is in its developing stage, there still exists flaws that id unsuitable for industrial applications: lack of determinism and real-time property, no unified application layer protocol and lack of synchronization between net nodes.It can be found that the motion control network system has the requirements of the high performance real-time data transition and fast synchronous motion from the analysis of high performance motion control model. It is summarized that the previous study about real-time and synchronization of Ethernet and analyzed a few common industrial Ethernets used for motion control. On reference of the IEEE802.3 protocol and China standard Electrical equipment of industrial machines--Serial data link for real-time communication between controls and drives, an innovative real-time and synchronous control network over Ethernet is presented. A bus topology and working method are applied to the net structure. According to ISO/OSI model, reference model for network interconnection is established. The message structure and contents of real-time and synchronous network are defined. The network timing and synchronization mechanism are also provided.The working principle of MAC_IP is analyzed and the key functional modules of MAC layer are given in this thesis. The implementation of IEEE802.3 MAC (Media Access Control) function is designed based on Altera's FPGA in this dissertation. Verilog HDL is used for this project. It lays the foundation for the design the MAC_IP that fulfills the real-time and synchronous network protocol. It also describes that the solutions to such as Top module, Tx Module, Rx module, MAC-control and interface between PHY, MAC and host, arithmetic for CRC, CSMA/CD, and Hash Table in this thesis.Control node with network interface is the basic element of network control system. With analysis of actual control system requirements, the motor control node is developed on real-time and synchronous network which includes power design, the Ethernet PHY interface design, SPI interface design, control unit (MCU), FPGA design and motor control interface. The QEP circuit is also designed in FPGA. The develop method of control model with network interface is illustrated. The IP core's synthesis and assemble ate based on develop tool Quartus II. At last, design module is downloaded in motor control model. It is testified the feasible of the development of real-time and synchronous network by the test of no missing packet and no error packet.Finally, it presents some conclusion of the dissertation and expresses opinions on future work about real-time and synchronous network. It includes the solution of how to develop real-time software in the controller, device interoperability techniques and application layer protocol compatibility, the development of configuration application software and the development of actual application object based real-time and synchronous network.