The Software Of The Plc Platform For Research And Development

In order to overcome the shortages of the traditional hard-PLC and meet the users' demands of low-cost, strong compatibility and openness, this topic researches and develops a platform for SoftPLC which is according to the international standard IEC61131-3.The topic has established a frame for the platform of this SoftPLC. The platform is composed of three functional modules: human-computer interface, ladder diagram editor and the language transformation module. The operational principle of this system includes three parts. First, users edit ladder diagram or instruction list with the editors. Secondly, transform the ladder diagram or the instruction list into the general data structure. Finally, the general data structure is transformed into ladder diagram, the instruction list or structure tree. Then the topic realizes the transformation from ladder diagram into instruction list, the transformation from instruction list into ladder diagram and transformation from ladder diagram into structure tree.In the ladder diagram, a rung is composed of several logical blocks and several nodes, and a logical block is composed of several nodes too. The drawing of ladder diagrams uses the "total-section" analysis way. The topic uses the COMPOSITE Design Pattern to perform the drawing of the ladder diagram, in this way we have increased the execution speed and reduced the workload.In the designing of the system's kernel module- language transformation module, the topic uses the COMPOSITE Design Pattern to realize the transformation from ladder diagram into instruction list; uses the JAVA programming language's JTree class to implement the function of the transformation from ladder diagram to structure tree; uses the thought of stack to actualize the transformation from instruction list into ladder diagram.Combining with MVC ideology and Document/View construction, this topic uses JAVA programming language which can operate on different platform in designing the prototyping system. At last, the paper shows the operation guide and the operational aspect with a typical case. The result indicates that this system is simple to use, reliable and its using is strong.