Development Of WK1G PLC Programming Software Framework And Ladder Diagram Programming System

This article researches and develops the PLC programming software of independent intellectual property right,completes the construction of V1.0 edition,finishes the construction of the programming software framework,establishes the basic programming interface,realizes the basic function such as ladder diagram entry,editing,conversion.Under the impetus of international industrial communication standards,engineering control language standards,and control scale,PLC programming software has gradually developed toward an open and unified fully integrated automation software architecture.Based on the IEC61131-3 standard,this article focuses on the research of key technologies such as the programming system framework,ladder diagram editor,and the algorithm of transforming ladder diagram into instruction table in the PLC programming software,the main content of the completion is as follows(All the development work involved in this paper is done in the Qt Creator integrated development environment with C++ language.):(1)Based on the fully integrated automation software architecture,with the goal of uniformity and openness,detailed comparisons are made between the data types,variables,program organization units and other elements of the industrial control programming language standard IEC61131-3 with the traditional PLC system,finally,based on the software model in IEC61131-3 standard,the overall framework design of PLC programming module is achieved.(2)Based on the IEC61131-3 standard,the PLC programming module is divided into file module,configuration module,program module,conversion module,compilation module,interface module,and control module.This article completes the PLC programming system framework design,custom data types,program organization unit,configuration,resources,variables and other IEC61131-3 software model elements to create,add,edit and orderly management.(3)Based on the IEC61131-3 standard,a network topology with a relatively high degree of freedom is used to describe the ladder network.According to the topology structure,a distributed ladder diagram primitive storage relationship is proposed,and the data structure design of the storage model is completed.The storage structure stores the storage relationships between the graphics elements in the graphics elements and the connection lines,avoiding complicated data structures.(4)Based on the graphic/view framework in the Qt interface library,an object-oriented programming approach is used to complete data structures of ladder diagram primitives and property editor interface design such as annotations,contacts,coils,power rails,and standard function/function blocks through inherited methods.Finally,achieve the drag and drop element,click to add,the establishment of the connection relationship of the element and the deletion of the element.(5)Based on the ladder network topology,an algorithm for transforming a ladder network into an instruction table is proposed and implemented.The algorithm scans the entire ladder network through a left to right","top to bottom scanning mode to identify the three connection relationships and connection errors,the connection relationships are between serials,parallels,and branches of different primitives,in the same time,represent this connection relationship as a logical tree.The primitive is scanned as the leaf node of the logical tree,and the connection relationship is scanned as the root node.Finally,the entire logical tree forest is scanned by the pre-order traversal algorithm to complete the conversion of the ladder diagram to the instruction table.