远动规约三种传输模式实时性分析及其设计考虑

Real time analysis and design consid erations of telecontrol protocol 's three transmission modes

根据DNP(DistributedNetworkProtocol)规约数据链路层类FT3帧及其校验方式,推导出帧传输失败概率(误帧率)与通道误比特率和帧长的关系,同时给出平均传输次数和重复传输次数的计算公式。在此基础上结合远动信息传输实时性的要求,分析远动规约三种传输模式的实时性,并根据传输特点提出了设计考虑和优化方法。在问答式传输模式中,论述了为保证1类数据的实时性主站询问子站的时间间隔的选取方法和选取范围;在循环式传输模式中,讨论了为兼顾信息传输的可靠性和有效性子站采用重复3次传送重要信息的可行性和必要性,并确定了重复传送次数最优值的选取区间;在主动上送式传输模式中,指出了在具体站的配置下传输速率与误比特率选取的约束关系。

According to Similar FT3frame 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.In addition,the computation formulas of average transmission times and repeat transmission times guaranteeing the correct transmission of telecontrol information are given.Based on the computation formulas and the real time performance demand of information transmission,the real time perfor-mance of three transmission modes is analyzed.The design considerations and optimization means of three modes are proposed according to their transport characters.In polling mode,the selection way and extension of polling interval of master polling outstation are illustrated in order to ensure the real time performance of Class1data.In cyclic data transition mode,the feasibility and necessity of outstation repeatedly transferring important information three times is discussed in giving atten-tion to reliability and validity of information transmission,and the choice range of optimized repeat transmission times is confirmed.In un solicited response mode,the constraint relationship between transmission velocity and BER is presented in the case of station configuration.