Analysis And Design Of CAN Communication In CGSE Control System

This paper focuses on the design and implementation of data transportation and communication in CGSE Control System, including communication system architecture design, module design and implementation of communication system, data exchange design and protocol encasement, data demonstration and backup system, driver model design and implementation. Hardware design of the system—Siemens S7-400H redundant PLC is applied as the controller, with distributed signal-collecting stations cascaded through Profibus network, and the communication between PLC and IPC is realized through Siemens CP5613A2 card. PCs equipped with EPP-CAN Boxes and Ethernet-Cards link both CAN and Ethernet, thus making up the Communication Interface System. Software design of the system—design and develop the client program and ActiveX component with Visual C++ MFC architecturem, the network communication program based on TCP stream and Socket Windows/Linux Technology, and the driver model of CAN-Bus and Ethernet under Linux.The main task of the system includes: communication protocol and data formttiong conversion, the design of Linux driver, socket technology application across different platform, modulization and combination of communication system. The communication protocol mainly refers to stability and compatiency, ensuring successful data communication while keeping the common information channel for other sub-system. Data formatting depends on the realization of communication protocol. Our system brings in two different communication methods, including CAN and Ethernet. And also, we design different data formatting for them respectively. Driver layer mainly depends on communication interface and hardware platform, meanwhile bringing Linux features. The driver in our system provides the interface to hardware platform and the interface to application layer. The FEP communication software realizes IPC and Ethernet data transfer both by socket technology. We keep the Ethernet feature of FEP but change the IPC method to named pipe which is aimed to higher efficiency. We also divide the system into separated modules as its large scale and multiple-functions. Additionaly, our system brings in several useful funtions as good GUI, data backup and second-development. The client PC realizes GUI for convenient use. Data backup function refers to database demonstration. As we considered the limit from platform and operating system, there's no DBMS included. On the contrary, we use direct database reading and writing. For more flexible development, we design a second-development component for our system.The system test result shows that the design approaches proposed in this paper are stable, reliable and easy to maintain.