BDD & STM: HeaterControl

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TRAIL: SysPhS-1.1 Annex A examples in MagicDraw/Cameo SysML vs Modelica (Wolfram SystemsModeler)

Section

Annex A.5: Humidifier (with Units)

Tags and keywords

Topic level

UML keywords

TimeEvent::when

SysML keywords

SysPhS Keywords

IntegerSignalInElement

RealSignalInElement

Modelica keywords

Keywords

Slide kind

SysML Block Definition Diagram (BDD)

SysML StateMachine Diagram

This diagram shows the Block HeaterControl with a supporting StateMachine HeaterControlSM:

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As long as the iMode.iSig switch is 1 (on) the HeaterControlSM will cycle between Off and On as it tries to drive the heater to achieve the targetHumidityPct, comparing it with the input iHumidityPct.rSig, subject to a small thresholdPct.

The heater power ratio is set to either fully on (1.0) or fully off (0.0).

If it receives an iMode.iSig switch 0 while in the On state it moves to Off.

Remember always that:

SysPhS-1.1 vs Modelica: On export the SysPhS signal flow Port types are flattened to remove the FlowProperty (rSig, iSig, or bSig). In the exported Modelica code you'll only ever see the Port names.

The heater power ratio is sent via the Port oHeaterPowerRatio to the VaporGenerationPlant, so let's now dive in and examine it.

Up next

BDD & IBD: VaporGenerationPlant

Notes

[MODELLING, NAVIGATION, PATTERN, TIP, TOOL]{STRONG} Webel: UML/SysML: Navigation: ALWAYS offer a way out of a diagram (usually up a hierarchy, but possibly across) using a navigable symbol (linked to a diagram) and/or a diagram symbol. Avoid "cul-de-sacs"! [But beware of shared package cross-dependencies]

[CAPABILITY, FEATURE, TOOL] MagicDraw/Cameo: Supports embedding of one or more Diagrams in another via the Diagram Overview feature. Awesome!

[CONVENTION, DISPLAY, MODELLING, STYLE, TIP]{STRONG} Webel: SysMLv1: Highly recommend creating a "focus" Block Definition Diagram (BDD) for each main Block with expanded feature details and relationships to at least nearest neighbours

[NAMING, TIP]{OPTION} Optionally suffix the "focus" BDD for a Block with '.bdd' so that it won't clash with a corresponding IBD on diagram export. This is not a SysMLv1 concern, it is purely a workflow concern. It has the slight disadvantage that BDD may "indicated" twice.

[DISPLAY, STYLE, TIP, TOOL]{SUGGESTED} Style: use line width 2 or 3 on the border of the "focus" element in "focus" diagrams (such as the main Block or Class of a dedicated Block Definition Diagram or Class Diagram)

[CONVENTION, MODELLING, NAMING, TIP]{STRONG} Webel: If you must name your Ports or Pins, name them simply 'i', 'o', or 'io' (or 'oi') to indicate direction UNLESS you have to indicate a special role like 'iRole', 'oAuxiliary'. DO NOT use Port or Pin names like 'input', 'output', etc.

[GOTCHA] Modelica does not support comparison of Real values using == outside of functions (so not directly inside state machines)

[DISPLAY, MODELLING, TIP, TOOL]{INFORMATIVE} MagicDraw/Cameo: Display options: On an 'entry', 'doActivity', or 'exit' Behavior of a State you may choose to display the specification code of an OpaqueBehavior or just its name.

[ISSUE, MODELLING, TIP, WARNING] GOTCHA: MagicDraw SysML/Cameo 19SP3: Export to Modelica: 'entry', 'doActivity', or 'exit' Behaviors of a State must be directly owned (not just "wrapped") or they won't be seen on export!

[GOTCHA, MODELLING, TIP, WARNING] MagicDraw SysML/Cameo 19SP3: GOTCHA: If you drag a Behavior from the model browser onto the 'entry', 'doActivity', or 'exit' field in a specification dialog of a State it WILL BECOME OWNED by the State (which "steals ownership")!

[TIP]{INFORMATIVE} SysPhS-1.1 vs Modelica: On export the SysPhS signal flow Port types are flattened to remove the FlowProperty (rSig, iSig, or bSig). In the exported Modelica code you'll only ever see the Port names.

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Figure 27: Default values and initial value in SysML

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