多功能车辆总线系统性能分析

现场总线技术在铁路通信领域起着关键作用,分析、评估总线网络的性能可以指导合理的网络配置。本文介绍了多功能车辆总线的数据类型,数据的传输特点以及数据的传输内容。该总线采用周期轮询的介质访问控制方式,在轮询周期内,主设备发送轮询帧,从设备发送响应帧。结合现有地铁车辆故障诊断系统的实际情况,介绍车辆级故障诊断系统的车辆编组结构、控制网络的配置以及系统参数的设定等情况,进而建立数学模型,分析该系统的轮询周期、报文分组在服务站内的平均等待时间,利用排队理论分析网络的延迟性能以及服务站缓存器的容量问题,与实际情况及一般经验参考公式做对比分析,得出系统轮询周期的经验参考值与实验分析值之间的对比结果,提出了该总线网络的性能分析方法。

Performance Analysis of Multifunction Vehicle Bus System

Fieldbus plays a key role in railway communication domain.Analyzing and evaluating the network performance can direct suitable network configuration.The paper discusses the data types,data transmission and data contents of Multifunction Vehicle Bus(MVB).The polling medium access control scheme is adopted in MVB.In the polling cycle,the master device sends the polling frame and the slave device sends the variable's value in a slave frame.In combination with the case of the Fault Diagnosis System(FDS) for metro vehicles,the paper discusses the vehicle formation groups,network configuration and paramenter setting,and establishes mathematical models.It analyzes the polling cycle time and the packet waiting time in the server.It also analyzes the network delay performance and the server memory capacity by the queuing theory in contrast with the practice and obtains the results.Finally,it proposes the performance evaluating method for MVB.