Profibus-DP单主站系统实时性研究

摘要

分析了Profibus-DP协议数据链路层的运行机理,详细描述了构成Profibus-DP总线周期的时间参数,给出了报文循环时间、令牌目标轮转时间和系统反应时间这三个Profibus-DP系统实时性能指标的具体计算公式,并结合Profibus-DP单主站系统实例,通过测算系统反应时间分析了影响Profibus-DP单主站系统实时性的因素,最后提出可通过提高通信速率、减少从站数量、减少交换数据量来提高Profilbus-DP单主站系统实时性.%The paper analyzed operating mechanism of data link layer of Profibus-DP protocol,described time parameters that compose Profibus-DP bus cycle in details, and gave concrete calculating formulas of real-time indexes of Profibus-DP system named message cycle time, token target rotation time and system reaction time. Combining an example of some Profibus-DP single master-station system, it analyzed factors which affect real-time performance of Profibus-DP single master-station system through calculating system reaction time, and finally proposed methods to improve real-time performance of Profibus-DP single master-station system, including improving communication speed and decreasing number of substations and changed data.