An approach to SysML modeling of IEC 61131-3 control software

Designing, developing, and maintaining control software is often a complex and difficult task, especially in larger projects. The paper presents a concept of applying the Model-Driven Development approach with SysML modeling to the IEC 61131-3 development process. Four types of diagrams are used to model different aspects of the system: Requirements Diagram, Package Diagram, Block Definition Diagram, and State Machine Diagram. The models represent POUs and their requirements, resources, and tasks. Some POUs can be modeled as state machines as well. The SysML diagrams can be used to generate code templates for the implementation in IEC 61131-3 languages, such as ST or FBD. The paper also describes an extension to the CPDev engineering environment, which integrates the proposed SysML modeling with programming and execution of IEC 61131-3 software. The example of an engine and pump control system is presented to show various stages of the proposed approach.