To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By...To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By analyzing information transmission regularity and EPA deterministic scheduling mechanism,periodic messages were categorized as different modes according to their entering-queue time.The scheduling characteristics and delivery time of each mode and their interacting relations were studied,during which the models of real-time performance of periodic information transmission in EPA system were established.On this basis,an experimental platform is developed to test the delivery time of periodic messages transmission in EPA system.According to the analysis and the experiment,the main factors that limit the real-time performance of EPA periodic data transmission and the improvement methods were proposed.展开更多
本文分析了网络制造环境下离散制造企业车间数字设备控制模式及其控制网络的拓扑结构;提出了基于EPA(Ethernet for Plant Automation)协议的车间数字设备集成控制系统的体系结构;设计了集成控制网络系统的结点结构和通信协议转换器;利...本文分析了网络制造环境下离散制造企业车间数字设备控制模式及其控制网络的拓扑结构;提出了基于EPA(Ethernet for Plant Automation)协议的车间数字设备集成控制系统的体系结构;设计了集成控制网络系统的结点结构和通信协议转换器;利用嵌入式技术实现了车间数字设备与工业以太网间信息的透明传输。展开更多
为了提高EPA(Ethernet for Plant Automation)系统的通信实时性能,在EPA确定性通信调度策略的基础上,提出了一种控制与通信的同步方法.该方法将EPA设备的通信宏周期划分为通信时间片和控制时间片;程序在每次巡回执行时获取当前时间,并...为了提高EPA(Ethernet for Plant Automation)系统的通信实时性能,在EPA确定性通信调度策略的基础上,提出了一种控制与通信的同步方法.该方法将EPA设备的通信宏周期划分为通信时间片和控制时间片;程序在每次巡回执行时获取当前时间,并根据当前时间是位于通信时间片内还是控制时间片内来决定执行通信任务还是控制任务;在执行控制任务时,使用设置和扫描状态标识的方式保证功能块在通信宏周期中的单次执行.实验表明,该方法能够有效避免EPA系统中功能块的无效执行和数据的无效传输,提高系统的通信实时性能.展开更多
基金Supported by the National High Technology Research and Development Program of China (2006AA040301-4,2007AA041301-6)
文摘To evaluate and improve the real-time performance of Ethernet for plant automation（EPA） industrial Ethernet,the real-time performance of EPA periodic data transmission was theoretically and experimentally studied.By analyzing information transmission regularity and EPA deterministic scheduling mechanism,periodic messages were categorized as different modes according to their entering-queue time.The scheduling characteristics and delivery time of each mode and their interacting relations were studied,during which the models of real-time performance of periodic information transmission in EPA system were established.On this basis,an experimental platform is developed to test the delivery time of periodic messages transmission in EPA system.According to the analysis and the experiment,the main factors that limit the real-time performance of EPA periodic data transmission and the improvement methods were proposed.
文摘为满足EPA网络控制系统时间同步的高精度要求,由EPA子网通讯确定性调度机制构建虚拟链路,建立基于时钟精度差的多层次主时钟选择算法。引入IEEE1588时钟变量σPTP,动态调整时钟精度偏差(CPD:Clock Precision Difference)与时间值偏差(TVD:Time Value Difference)为权重的时钟优先级(CP),建立一种二维模糊控制器确定设备时钟性能优劣层次,而系统采用公平竞争的方法从众多现场设备中快速、准确地决策一个时钟性能最好的设备作为EPA系统的最佳主时钟,保证了系统运行的稳定性,降低了本地时钟的波动,使时钟同步精度提高到50微秒。
文摘本文分析了网络制造环境下离散制造企业车间数字设备控制模式及其控制网络的拓扑结构;提出了基于EPA(Ethernet for Plant Automation)协议的车间数字设备集成控制系统的体系结构;设计了集成控制网络系统的结点结构和通信协议转换器;利用嵌入式技术实现了车间数字设备与工业以太网间信息的透明传输。
文摘为了提高EPA(Ethernet for Plant Automation)系统的通信实时性能,在EPA确定性通信调度策略的基础上,提出了一种控制与通信的同步方法.该方法将EPA设备的通信宏周期划分为通信时间片和控制时间片;程序在每次巡回执行时获取当前时间,并根据当前时间是位于通信时间片内还是控制时间片内来决定执行通信任务还是控制任务;在执行控制任务时,使用设置和扫描状态标识的方式保证功能块在通信宏周期中的单次执行.实验表明,该方法能够有效避免EPA系统中功能块的无效执行和数据的无效传输,提高系统的通信实时性能.
