What is SysML? The Systems Modelling Language Explained

The Systems Modelling Language (SysML) is a general purpose modelling language for engineering systems. SysML supports the analysis, design and verification of complex systems including hardware, software, information, personnel, procedures, and facilities in a graphical notation. SysML provides graphical representations based on a semantic foundation for modelling system behaviour, requirements, structure, and parametrical elements which are used to integrate with other engineering analysis models using the OML XML Metadata Interchange (XMI®).

SysML is defined as an extension of a subset of the Unified Modelling Language (UML) using UML’s profile mechanism and was submitted to the Object Management Group (OMG) in November 2005. A number of competing specification proposals were merged and adopted by the OMG as OMG SysML in July 2006.

Relationship between SysML and UML

The UML-SysML Relationship

SysML uses the concept of the ‘block’ as the basic unit structure to represent hardware, software, information, personnel, procedures, and facilities. Block definition diagrams and internal block diagrams are used to represent a system structure as illustrated below:

SysML Diagram Types

SysML Diagrams

The SysML Behaviour Diagram includes:

  • SysML Use Case Diagram – high level description of functionality delivered through interactions between parts of the system
  • SysML Activity Diagram – Illustrates the flow of data and control between activities
  • SysML Sequence Diagram – interactions between collaboration parts of the system
  • SysML State Machine Diagram – identifies transitions occurring in response to events in the system

The SysML Requirements Diagram identifies requirements hierarchies and derivation. Satisfy and verify relationships allow a requirement to be related to a model element that satisfies or verifies the requirements. This diagram acts as the connection between typical requirements management tools and system models.

The SysML Parametric Diagram identifies constraints on system property values such as performance, reliability and mass properties. It provides the ability to integrate the specification and design models with engineering analysis models.

An Allocation Relationship is also supported within SysML which represents allocating functions to components, logical to physical components, and software to hardware.

To understand more about SysML and develop the ability to apply it in a real world situation, book a place on our Systems Engineering with SysML Training Course and visit our UML Introduction to learn about the Unified Modelling Language.

SysML is a trademark of the Object Management Group.

Object Management Group


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