Study,Application And Realization Of Peer To Peer Telecontrol Protocol

The typical peer to peer telecontrol protocol DNP 3.0 is analyzed on the real time performance of data transmission , the transparency of layered function and the scientificity of frame format definition.The valid classification method and the gathering procedure of telecontrol information are presented so as to improve real time performance of telecontrol information transmission. The rules to be obeyed in program realization are summed up in insuring the reliability of telecommand and teleadjusting. The reason of synchronized error of DNP time synchronization is analyzed, and the improved means is given. A feasible way to realize parameter setting of telecontrol technology is put forward.According to Similar FT3 frame format and its checkout mode of DNP Data Link Layer, the relationship between FER( Frame Error Rate)and BER(Bit Error Rate), frame length is deduced. The computation formulas of average transmission times and repeat transmission times guaranteeing the correct transmission of telecontrol information are given as well. On the basis of such formulas and the demand of the real time performance of information transmission, real time behavior of three basic transmission modes are analyzed. Design considerations and optimization of the three modes are proposed according to their transport characters. In polling mode, the way to determine the polling interval of a Master station to ensure the real time performance of Class 1 data is illustrated. In cyclic data transition mode, the feasibility and necessity of an Outstation keeping on transferring important information three times so as to obtain both reliability and validity of information transmission is discussed. The optimum times of transmission is also talked about. In peer to peer mode, the constraint between transmission rate and BER in the case of a certain configuration is detailed.The external interface and internal structure of telecontrol protocol program is designed, three optional route of total program design are analyzed. The tactic of effective dividing of the program function is discussed, the effective way to divide the program function is presented in term of transparency. Application , transport and data link layers of Master station is designed and realized with VC++. The developed program is successfully used in the projects of distribution automation.