Graphics editors in CPDev environment

Abstract: According to IEC 61131-3 norm, controllers and distributed control systems can be pro-grammed in textual and graphical languages. In many scenarios using a graphical lan-guage is preferred by the user, because diagrams can be more legible and easier to understand or modify also by people who do not have strong programming skills. What is more, they can be attached to the documentation to present a part of a system implementa-tion. CPDev is an engineering environment that makes possible to program PLCs, PACs, softPLCs and distributed control systems with the usage of languages defined in IEC 61131-3 norm. In earlier versions, it supported only textual languages – ST and IL. Cur-rently, graphics editors for FBD, LD and SFC languages are also available, so users can choose a suitable language depending on their skills and a specificity of a program that they have to prepare. The article presents implementation of the graphics editors, made by the author, which support creating program organization units in all graphical languages defined in IEC 61131-3 norm. They are equipped with a set of basic and complex function-alities to provide an easy and intuitive way of creating programs, function blocks and func-tions with visual programming. In the article the project structure and some important mechanisms are described. They include e.g. automatic connections finding (with A * algo-rithm), translation to ST code, conversion to and from XML format and an execution mode supporting multiple data sources and breakpoints