WaterProcessingPlant - FlowProperty and ItemFlow example with Ports - type staging

There is a hierarchy: abstract H2O, Water in the 'liquid' state, and Steam in the 'gas' state. We are going to ignore the subtleties of 'water vapor' and hope our processing plant does not ever 'ice' up.

Note that in the Water and Steam blocks the state: StateKind value property is redefined and readonly.

The Webel Best Practice naming convention for Ports with flows has been used on F_Water and F_Steam:

Webel Best Practice: Webel: For SysML Blocks and InterfaceBlocks used to type Ports with physical flows use 'F_UpperCamelCase' [may be combined with acronymn conventions]. The trailing part (after the underscore '_') may indicate the type that flows.

Note also that each FlowProperty is anonymous because we can "Trust the Type" here:

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!

The default flow direction has been chosen as 'out' (source to sink):

Webel Best Practice: For Blocks and Interface blocks with one or more FlowProperty items, choose a direction convention and use it across one project.

In most Webel examples, the default is chosen to be 'out' if there is a single FlowProperty, so a Port with the type applied will act as a source. If an InterfaceBlock is used, then a Port typed by the conjugating ~InterfaceBlock will act as a sink.

And this trick has been used:

Place your SysML-1.6 ~InterfaceBlock conjugation under the 'original' InterfaceBlock (i.e. make the original the containment owner).

We connect the parts up next via their Ports.

ASIDE: Showing port symbols on the boundary of Block symbols is not regular Webel Best Practice, it's done here just for illustration:

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.

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WaterProcessingPlant - FlowProperty and ItemFlow example with Ports (in BDD with structure)

Notes

[NAMING, POLICY]{STRONG} Webel: For SysML Blocks and InterfaceBlocks used to type Ports with physical flows use 'F_UpperCamelCase' [may be combined with acronymn conventions]. The trailing part (after the underscore '_') may indicate the type that flows.

[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.

[NAMING, POLICY, STYLE]{STRONG} 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!

[POLICY] For Blocks and Interface blocks with one or more FlowProperty items, choose a direction convention and use it across one project.

[CONVENTION, STYLE]{RECOMMENDED} In most Webel examples, the default is chosen to be 'out' if there is a single FlowProperty, so a Port with the type applied will act as a source. If an InterfaceBlock is used, then a Port typed by the conjugating ~InterfaceBlock will act as a sink.

[TIP] Place your SysML-1.6 ~InterfaceBlock conjugation under the 'original' InterfaceBlock (i.e. make the original the containment owner).

[TIP, WORKAROUND]{INFORMATIVE} [HISTORICAL] HOWTO easily "hack" the SysML-1.6 ~InterfaceBlock conjugation and «~interfaceBlock» keywords in MagicDraw/Cameo. [NOW SUPPORTED 2024x Golden]

[TIP] A SysML Enumeration is a UML Enumeration with ValueType applied (so properties typed by it will list as value properties in the 'values' compartment on a Block)

Snippets (quotes/extracts)

[SysML-1.6] A FlowProperty signifies a single flow element to/from a block. A flow property has the same notation as a Property only with a direction prefix (in | out | inout). Flow properties are listed in a compartment labeled flow properties.

[SysML-1.6] Item flows specify the things that flow between blocks and/or parts and across associations or connectors.

[SysML-1.6] FlowProperty::1_restricted_types A FlowProperty shall be typed by a ValueType, Block, or Signal.

[SysML-1.6] ItemFlow::2_type_restricted An ItemFlow itemProperty shall be typed by a ValueType, Block, or Signal.

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Visit also (backlinks)

SysMLv1: An ItemFlow without an assigned 'itemProperty' is sometimes informally/casually referred to as an "information flow", especially when applied to an Association (because it is much like a UML InformationFlow), but formally it is a SysML ItemFlow.