調度策略是網絡控制系統(tǒng)中的一個重要問題。本文分析了常見調度算法的基本特點，并根據熱工自動控制系統(tǒng)的要求提出了一個基于緊急度指標（EI）的動態(tài)優(yōu)先權調度算法，機理分析和仿真試驗表明，此算法可以有效地提高總線利用率，保證系統(tǒng)的實時
性，防止數據丟失。
關鍵詞網絡控制系統(tǒng)調度算法現(xiàn)場總線
Abstract Scheduling strategy is a very important issue in Network Control Systems（NCS）. This paper analyses the scheduling algorithms used widely
and their features. In addition，a new scheduling algorithm with dynamic priority based on Emergence Index（EI）is presented for automatic process control.
Theoretical analysis and simulation show that by using this algorithm，the utilization ratio of the bus is enhanced effectively，the real-time performance
of the system is guaranteed，and data loss is prevented.
Key words Network control system Scheduling algorithm Fieldbus