一、引言目前,国内微处理机(特别是单板机)在实时控制方面的应用已经越来越多,但是控制对象一般比较简单。要对一条生产线、一个车间甚至整个工厂实现自动控制和管理,一台微处理机的容量和速度是达不到的。另外,对处理任务多、控制规律复杂、信息传输距离远、可靠性高等提出更高要求。在这种情况下,现在的发展趋势是采用多台微处理机组成分级分布控制系统。图1就是一个连续化工生产过程计算机控制系统的示意图。在这个例子中,三级计算机担负不同的功能,分别有自己的数据库。三级计算机之间由数据高速公路连接,可以互相传送信息,并共享系统的资源。另外还要有各种显示设备和控 I. INTRODUCTION At present, the application of domestic microprocessors (especially single-board computers) in real-time control has been more and more, but the control object is generally relatively simple. To automate control and management of a production line, a shop, or even an entire plant, the capacity and speed of a microprocessor are unattainable. In addition, the processing tasks and more complex control laws, information transmission distance, high reliability and higher requirements. In this case, the current trend is to use multiple microprocessors to form a hierarchical distribution control system. Figure 1 is a schematic diagram of a continuous chemical production process computer control system. In this example, three computers have different functions, each with its own database. Three computers connected by a data highway, you can send information to each other and share system resources. In addition there are a variety of display equipment and control