REFERENCE CARD: Types of Block Properties and Block compartments

Gallery

Tutorial

TRAIL: Webel's ultimate guide to Systems Modeling Language (v1) with MagicDraw/Cameo

Section

08:01: The building Blocks of SysML

Tags and keywords

Topic level

UML keywords

BehavioredClassifier::classifierBehavior

ParameterDirectionKind::in

ParameterDirectionKind::return

operations compartment

receptions compartment

SysML keywords

Keywords

ISO-80000

Slide kind

SysML Block Definition Diagram (BDD)

This slide is a comprehensive Block reference card we'll be using throughout this entire tutorial. If you feel a bit overwhelmed by this slide, please visit first this previous slide with explanations of the main Block compartments in a Block Definition Diagram (BDD) and this previous slide on the main symbols used in an Internal Block Diagram (BDD):

Click on the image to view it full size

Don't worry if you don't understand all of it yet, we'll be treating each aspect in dedicated trail sections throughout this tutorial. And remember:

SysML Blocks have lots of possible features and compartments, lots of capabilities, and are very powerful! But you don't have to use every aspect of a Block (or show every aspect in every diagram) at once on every project.

In general, the SysML DirectedFeature approach is more powerful and the notation is cleaner than UML provided/required Interfaces. Prefer SysML DirectedFeatures unless you have a really good reason to use Interfaces!

We show next a simplified "property cheat sheet".

Some remarks on modelling style

Please note that in addition to Ports being listed in compartments, their Port symbols are shown additionally here on the boundary of BDDs solely to show that it can be done. This is not usual Webel Best Practice:

Webel Best Practice: SysMLv1: Prefer not show Port symbols on the boundary of Block symbols in BDDs, just list them in compartments. One can't connect them in a BDD anyway. Recommend only show Port symbols in IBDs.

Please note also that use of verbose Property names is not usually advised:

Webel Best Practice: SysML: Webel: "Trust the Type!" - Often the name of the Type of an anonymous Property or instance-level element is completely sufficient to indicate its role - unless multiple Properties of the same Type have different roles within the same owner context!

Up next

REFERENCE CARD: Property cheat-sheet for Block

Notes

[ISSUE, NAMING, TOOL] MagicDraw/Cameo v19SP3: uses the Block compartment name 'signal receptions' instead of just 'receptions'. [CLAIMED FIXED in v2021x]

[MODELLING, STYLE]{RECOMMENDED} SysMLv1: Prefer not show Port symbols on the boundary of Block symbols in BDDs, just list them in compartments. One can't connect them in a BDD anyway. Recommend only show Port symbols in IBDs.

[ASSERTION, TIP]{SUGGESTED} SysML Blocks have lots of possible features and compartments, lots of capabilities, and are very powerful! But you don't have to use every aspect of a Block (or show every aspect in every diagram) at once on every project.

[TIP]{STRONG} In general, the SysML DirectedFeature approach is more powerful and the notation is cleaner than UML provided/required Interfaces. Prefer SysML DirectedFeatures unless you have a really good reason to use Interfaces!

Snippets (quotes/extracts)

[SysML-1.6] Blocks provide a general-purpose capability to model systems as trees of modular components.

[SysML-1.6] A block can include properties to specify its values, parts, and references to other blocks.

[SysML-1.6] Blocks may also specify operations or other features that describe the behavior of a system

[SysML-1.6] Parametric diagrams include usages of constraint blocks to constrain the properties of another block.

[SysML-1.6] Constraint blocks provide a mechanism for integrating engineering analysis such as performance and reliability models with other SysML models.

[SysML-1.6] Flow properties specify the kinds of items that might flow between a block and its environment, whether it is data, material, or energy. The kind of items that flow is specified by typing flow properties.

[SysML-1.6] Full ports specify a separate element of the system from the owning block or its internal parts. They might have their own internal parts and behaviors to support interaction with the owning block, its internal parts, or external blocks.

[SysML-1.6] Proxy ports identify features of the owning block or its internal parts that are available to external blocks through external connectors to the ports. They do not specify a separate element of the system from the owning block or internal parts.

[SysML-1.6] SysML ValueType adds an ability to carry a unit of measure and quantity kind associated with the value.

[SysML-1.6] SysML establishes four basic classifications of properties belonging to a SysML Block or ValueType.

[SysML-1.6] A compartment with the label “receptions” may appear as part of a block definition to show signal receptions. The “«signal»” keyword is optional in this compartment.

[SysML-1.6] A property typed by a SysML Block that has composite aggregation is classified as a part property, except for the special case of a constraint property ...

[SysML-1.7] A property typed by a Block that does not have composite aggregation is classified as a reference property.

[SysML-1.6] A property typed by a SysML ValueType is classified as a value property, and always has composite aggregation.

[SysML-1.6] Part, reference, value, and constraint properties may be shown in block definition compartments with the labels "parts," "references," "values," and "constraints" respectively.

[SysML-1.6] Properties of any type may be shown in a "properties" compartment or in additional compartments with user-defined labels.

Visit also

Visit also (backlinks)

SysMLv1: TIP: You can strengthen the ill-defined semantics of Property 'aggregation' (an AggregationKind) by applying custom Stereotypes to a Property, documented with its intended use. Not perfect, but better than not. EXAMPLE: «assembled»

SysML: Syntax ain't Semantics: FUN CHALLENGE: SysMLv1 block property aggregation: 'The tornado chaser plane "has" a chaser car "with" a chaser team.'

Webel: SysML: Heard of "follow the money"? In MBSE we "follow the flows"! Identify requests, data packets, messages, signals early on and use ItemFlow as often as you can wherever you can! Adopt a signal processing mindset throughout (systems thinking).

SysMLv1: MagicDraw/Cameo: Oh no, I lost my part or reference property? Where did it go? The Symbol Properties option for 'Show Association ends as Attributes' may help you find it!

SysMLv1: A part Property or reference Property is not necessarily a 'memberEnd' or 'ownedEnd' of an Association ('association' or 'owningAssociation'). But an Association always as at least 2 'memberEnd' Properties. (With some MagicDraw/Cameo tool tips.)

Webel: SysMLv1: Overview of annotated Diagram Slides and Note pages related to general high level SysML modelling principles (some specific to MagicDraw/Cameo). Recommended reading for all Webel SysML/MBSE course attendees.

MagicDraw/Cameo: If you want to show a Property or Port listed both in its corresponding compartment on a Class or Block symbol and as the end of an Association in the same diagram, set the display option Show Association Ends As Attributes/Ports to 'all'

Related slides (includes other tutorials)

Related slides (backlinks, includes other tutorials)

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