BDD & PD: RelativeHumidityCalculation

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Tutorial
TRAIL: SysPhS-1.1 Annex A examples in MagicDraw/Cameo SysML vs Modelica (Wolfram SystemsModeler)
Section
Annex A.5: Humidifier (with Units)
Topic level
INTERMEDIATE
UML keywords
Property::redefinedProperty
ports compartment
Port
SysML keywords
Block
:values compartment
BindingConnector
constraint parameter
Keywords
Slide kind
hybrid diagram
SysML Block Definition Diagram (BDD)
SysML Parametric Diagram
This diagram shows the Block RelativeHumidityCalculation with a supporting ConstraintBlock RelativeHumidityCalculationConstraint:
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If satVap and press are both indeed simply pressures then:
Webel vs SysPhS-1.1: Annex A.5: Humidifier: Dimensional analysis of RelativeHumidityCalculationConstraint implies constraint parameter 'change' in {der(x)=((press/satVap)-change)/c2} is a unitless relative humidity, given that 'c2' is a Time.

This may seem obvious, but it's emphasised here because it has consequences "upstream" for both HumidityBalance and VaporPressureCalculation.

There are a couple of minor diagram errors in the spec:
SysPhS-1.1: Annex A.5: The BDD Figure 74 and Parametric Diagram Figure 84 for block RelativeHumidityCalculationConstraint are missing PhSConstant 'c2'. Compare with the constraint {der(x)=((press/satVap)-change)/c2} in BDD Figure 79.
SysPhS-1.1: Annex A.5: Typo in Figure 98 redefining value property 'C2 : Time = 1.0{redefines C2,unit = second}', should be lower case 'c2' (compare with BDD Figure 79)
That last one matters because:
GOTCHA: MagicDraw SysML/Cameo 19SP3: Export to Modelica: The name of a redefining Property must be exactly the same as the Property it redefines or it will not export properly!
Up next
BDD & PD: HumidityBalance
Notes
[ASSERTION]{STRONG} Webel vs SysPhS-1.1: Annex A.5: Humidifier: It is assumed that "vapor" is a volume rate corresponding to the rate of consumption OF HEATED LIQUID WATER (from a tank) used to create the vapor.
[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]
[MODELLING, PATTERN, TIP]{RECOMMENDED} SysML: When using Property::defaultValue and Property::redefinedValue to carry a "shadow hierarchy" of redefinitions across an entire system hierarchy, considering using a user-defined keyword such as «configuration» or «scenario» on each redefining Block
[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.
[CAPABILITY, FEATURE, STYLE, TIP]{RECOMMENDED} TIP: UML/SysML: MagicDraw/Cameo: Consider showing the constraint parameter name and type label inside the small rectangular parameter symbol on SysML Parametric Diagrams. Dr Darren swears by it!
[ISSUE] SysPhS-1.1: Annex A.5: Typo in Figure 98 redefining value property 'C2 : Time = 1.0{redefines C2,unit = second}', should be lower case 'c2' (compare with BDD Figure 79)
[ISSUE] SysPhS-1.1: Annex A.5: The BDD Figure 74 and Parametric Diagram Figure 84 for block RelativeHumidityCalculationConstraint are missing PhSConstant 'c2'. Compare with the constraint {der(x)=((press/satVap)-change)/c2} in BDD Figure 79.
[ASSERTION] Webel vs SysPhS-1.1: Annex A.5: Humidifier: Dimensional analysis of RelativeHumidityCalculationConstraint implies constraint parameter 'change' in {der(x)=((press/satVap)-change)/c2} is a unitless relative humidity, given that 'c2' is a Time.
[GOTCHA, ISSUE, MODELLING, TIP, WARNING]{INFORMATIVE} GOTCHA: MagicDraw SysML/Cameo 19SP3: Export to Modelica: The name of a redefining Property must be exactly the same as the Property it redefines or it will not export properly!
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Figure 27: Default values and initial value in SysML
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