XML based Visualization of the IEC 61131-3 Graphical Languages

Industrial process measurement and control systems (IPMCS) are used in most of the industrial sectors to achieve production improvement, process optimization and time and cost reduction. Integration, reuse, flexibility and optimization are demanded to adapt to a rapidly changing and competitive market. In fact, standardization is a key goal to achieve integration and reuse in this type of applications. The international standardization efforts have lead to the definition of the IEC 61131 standard. Part 3 of this standard defines a software model for defining automation projects as well as 5 programming languages (two textual and 3 graphical) emphasizing software reuse. Currently, a major part of programmable logic controllers (PLC) vendors offer programming tools that follow this standard. However, for achieving true reusability, interoperability among programming tools is required. The technical committee 6 of the international organization PLCopen has proposed a XML based interface to achieve interoperability. This paper analyses the PLCopen TC6 XML schema and proposes a novel approach based on separation of concerns: a XML file that describes the contents of POUs written in a graphical language and a scalable vector graphic (SVG) file that defines the graphical view of the same file. Both can be generated from a file compliant to the PLCopen TC6 XML schema. The XML file can be used to achieve interoperability while the SVG file can be used for generating documentation in graphical form.