可编程序控制器应用软件的结构化设计方法

本文通过引入现代软件工程的思想，紧密结合结合可编程序控制器独特的周期扫描运行机制，提出了梯形图的结构化设计方法。其设计过程分为三个步骤；一是利用功能表图建立对系统的功能描述；二 利用变换分析的方法建立软件的层次化模块结构；三是针对各功能模块，利用具体的梯形图指令实现各模块的功能。实现证明，这种方法 衣效地提高梯形图软件开发的质量和效率，适合于大型、复杂顺序控制系统梯形图应用软件的开发。

A STRUCTURED DESIGN FOR THE APPLI CATION SOFTWARE OF PROGRAMMABLE CONTROLLER

Following the more application of programmable controller technique in sequence program control system,more and more difficulties in ladder diagram programming with empirical design method occur. In this paper, by utilizing iheories of software engineering, we can easily make the structured design of ladder diagram, and the design progress is divided into three phases. The corresponding system function and control process are described by a function chart in the first phase. Then, the module structure is designed with the transform analysis method. Finally, the function of each module is realized by programming with instruction. sets of programmable controller. It is proved that this method is suitable for ladder diagram programming of complex sequence control system, and the productivity and quality of software developing are improved effectively.