摘要
根据EPA(ethernet for plant automation)系统中数据发送时间片的设置规则及其与确定性调度参数的相互作用机制,提出了一种数据发送时间片自适应调整方案EPA-TSA(EPA timeslice self-adaptive adjustment),该方案能够实现数据发送时间片根据网络负载的变化自动调整以使其利用效率得到提高.应用该方案,各个设备首先通过打时间戳的方法获得其数据发送需求时间,再调用自适应设置算法确定时间片自适应设置值,然后通过在非周期数据发送声明报文中增加字段的方法实现该值的传输,最后各个设备根据自适应设置值调整其确定性调度参数,以此完成数据发送时间片的调整设置.文中效果分析和实例分析表明该方案能够有效提高系统的实时性能.
Based on the setting rules of data transmission timeslice and the interaction mechanism between it and deterministic scheduling parameters in EPA （ethernet for plant automation） system, EPA-TSA （EPA timeslice self-adaptive adjustment） method is proposed to improve its usage efficiency, which accomplishes the self-adaptive adjustment of data transmission timeslice according to the variation of the network load. According to EPA-TSA method, each device in a micro-segment acquires its data transmission demanding time by means of generating a timestamp and uses it to calculate the timeslice self-adaptive setting value. Then, the device an- nounces its timeslice self-adaptive setting value to other devices in the micro-segment through adding new field in NDA （nonperiodic data annunciation） message. After receiving the timeslice self-adaptive setting values from other devices, a device uses them to adjust its deterministic scheduling parameters and accomplish the adjustment of data transmission timeslice. The analysis of an example shows that the method can improve the real-time per- formance of EPA system effectively.
出处
《仪器仪表学报》
EI
CAS
CSCD
北大核心
2009年第11期2298-2304,共7页
Chinese Journal of Scientific Instrument
基金
国家高技术研究发展计划(2007AA041301-6
2007AA041407)
教育部重大项目培育基金(706015)资助项目
