多任务环境下软PLC执行系统软件实时性分析

摘要

Aiming at the real - time performance requests of soft PLC, this paper advances a new a-nalysis model to calculate the schedulability of periodic tasks and the general response time of non - periodic tasks in hybrid real - time system based on Rate - monotonic Scheduling (RM). Time - demand a-nalysis method is used to handle with periodic tasks and the M/M/1/K queuing model is used to analyze non - periodic tasks. Finally the schedulability of the whole tasks is calculated to make sure all the tasks can satisfy their deadlines and the experiment show that the calculate result of the analysis model accords with the system real status.%针对软PLC执行系统的实时性能需求,基于RM调度策略,利用时间需求分析算法,对系统中所有周期任务进行可调度性分析测试,估计其最大响应时间是否满足时限要求.利用可延期服务器调度非周期任务,利用M/M/1/K排队模型,根据非周期事件接收缓冲大小及其到来随即过程相关参数,估计非周期事件的平均响应时间和缓冲溢出率,使之符合系统要求.