What’s new in SysML v1.7
Everyone is looking at SysML v2, but at the same time, a new version of SysML v1 has been released. The SysML v1.7 is very likely the last SysML v1 version. This blog post provides a brief overview of the changes in SysML v1.7.
You can download the SysML v1.7 for free from the official SysML page on the OMG website.
There are quite a few minor changes and two major ones. The minor changes also include many typos and rewordings. I will not explain them here. To keep the excitement going, here are the minor changes first.
allocatedFrom is now called allocated
The allocation relationship can be represented in the compartment of the elements involved if the notation of the element allows compartments. In the target element, the heading used to be “allocatedFrom”. With SysML v1.7, it is now simply called “allocated”.
The model element ConnectorProperty is marked as deprecated because the same functionality is provided by the model element AdjunctProperty.
The RaiseExceptionAction is part of SysML. It refers to the ExceptionHandler that was not part of SysML. The element is not part of the UML4SysML subset.
HSUV Sample Model
This is one of the bigger changes. The HSUV example model in Appendix D of the specification has been completely revised.
It contained some inconsistencies because the individual diagrams were not based on a uniform model before. Now the example model is consistent, and so are the diagrams and descriptions.
Precise Semantics for SysML
The second major change is a non-normative addition to SysML.
Both UML and SysML lack the specification of precise semantics. In purely descriptive models, this gap is usually not noticed, but as soon as one enters the field of simulations, it becomes apparent.
The UML specification is already flanked by supplementary specifications that specify the precise semantics:
- Semantics of a Foundational Subset for Executable UML Models (FUML)
- Precise Semantics of UML Composite Structures (PSCS)
- Precise Semantics of UML State Machines (PSSM)
They also apply to SysML. The new appendix H of the SysML v1.7 specification adds the precise semantics for specific SysML elements with execution semantics.
Among other things, this will help bridge the gap between SysML v1 and SysML v2, allowing for a cleaner transition from one version to the next. Only if one knows what exactly was specified in a SysML v1 – model, it can be transferred cleanly into the SysML v2.