Research On Deterministic Transmission Of Multimedia Date In EPA-Networks

With the continuous development of industrial information and automation, industrial control field includes not only the traditional real-time requirements of the measurement and control data, but also a variety of other data, multimedia data is the main component of the type of data. Industrial Ethernet deterministic transmission of control data and multimedia data becomes real demand. The paper research on the deterministic transmission of multimedia data in the EPA network, solve the problem of two types of data deterministic transmission, this thesis carries out the following works:1. Based on analysis of control data and multimedia data transmission demand characteristics, raised the problems faced by the industrial Ethernet transmission of multimedia data, that is how to ensure deterministic and real-time of the various types of data. Ethernet uses CSMA/CD MAC mechanism, the method is a non-deterministic communication scheduling, will cause uncertainty network collision. The timeshare send and priority call mechanism of EPA able to completely avoid packet collisions and uncertain delay, ensure deterministic and real-time data communication, raised the feasibility of multimedia data transmission in the EPA network.2. To schedules the parameters of the communications network, construction the transmission scheduling model of multimedia data in cycle time slice, completion of the single communication macro cycle and the chip length of the multimedia data, to solve the problems of the deterministic transmission in between the respective devices of the device layer; Network layer multimedia data fragment and reassembly in receiving end may cause multimedia data disorder and other uncertainties, a linked list insertion algorithm is proposed to achieve the orderly restructuring of the fragmented packets to solve the problem of a single multimedia devices communicate deterministic.3. Designed a kind of EPA-access card with protocol stack, construction network test platform-access multimedia data, realized multimedia data transmission in the EPA network, camouflage multimedia data for multi-terminal display and the deterministic transmission of the control data and multimedia data. On this basis, the multimedia data transmission delay and delay jitter dual indicators performance test, can meet the experimental setting expected of multimedia data’s performance indicators, with no disturbance to control data meanwhile, At last the feasibility of multimedia data deterministic transmit on EPA is examined.