Figure 65: Internal structure of the total humidifier system - black box vs details

The trail version here shows a composite image, the top Internal Block Diagram (IBD) is a black-box view much like the spec figure, the bottom one shows the Port types and exposes some internals via the :parts compartments:

Click on the image to view it full size

As indicated here using SysML ItemFlows, the measure of humidity HumidityPct is in fact a percentage.

The measure of the vapor (using US spelling) amount VaporRate_mL_per_h is in fact a rate in millilitre per hour, as hinted by the names of some of the conversion factors:

Webel vs SysPhS-1.1: Annex A.5: Assume the conversion value property names 'WaterTank::litpSec2mLitpHr' and 'EvaporationCalculation2::litPSec2mLitPHour' stand for 'litres per second to millilitres per hour'

We'll explore those blocks in more detail later.

There are some major problems with both the SysML-1.1 spec and the MagicDraw/Cameo sample implementations w.r.t. SysML-1.6:

SysPhS-1.1: Annex A.5: Humidifier: Use of UML-style direct Port conjugation not permitted since SysML-1.6, prefer ~InterfaceBlock type-based conjugation (example requires migration)

MagicDraw/Cameo v19SP3 vs SysML&SysPhS: The sample project for the Humidifier example uses DEPRECATED FlowPorts (and sets values directly on them in the StateMachines).

For most (but not all) Ports in this trail version the type is either RealSignalInElement or an explicitly conjugated SysML-1.6 friendly custom type ~RealSignalInElement, noting that:

In SysML the NOW DEPRECATED (since SysML-1.6) direct UML Port conjugation does not work consistently with SysML DirectedFeature and SysML FlowProperty on nested ports!

Unfortunately, the otherwise robust HACK for the SysML-1.6 «~interfaceBlock» promoted often on this Webel IT site does not play nicely with export to Modelica:

MagicDraw/Cameo v19SP3 vs SysML&SysPhS: GOTCHA: Will NOT correctly export a SysML-1.6 «~interfaceBlock» to Modelica (but does cope with a tilde ~ prefix in the name of a plain InterfaceBlock)

Therefore, a plain InterfaceBlock is used for the explicitly conjugated type ~RealSignalInElement (one might just as well have used the SysPhS RealSignalOutElement).

This trail systematically employs this Webel Best Practice:

Webel Best Practice: Webel: If you must name your Ports or Pins, name them simply 'i', 'o', or 'io' 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.

Before drilling down, we're going to look at the explicit Units and ValueType names used across the entire system in this highly elaborated trail version of the example, and then we'll inspect quickly also an overview of all Blocks in the entire system, which diagrams will serve as references you can return to at any stage.

Up next

REFERENCE: A.5 Humidifier: Webel: ValueTypes and Units

Notes

[ISSUE, WARNING] In SysML the NOW DEPRECATED (since SysML-1.6) direct UML Port conjugation does not work consistently with SysML DirectedFeature and SysML FlowProperty on nested ports!

[GOTCHA, ISSUE, TOOL, WARNING]{INFORMATIVE} MagicDraw/Cameo v19SP3 vs SysML&SysPhS: GOTCHA: Will NOT correctly export a SysML-1.6 «~interfaceBlock» to Modelica (but does cope with a tilde ~ prefix in the name of a plain InterfaceBlock)

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

[WARNING] Until tool support for ~InterfaceBlock comes you have to make a decision: (1) Bake your own «~InterfaceBlock» then deal with clashes when tool support comes; (2) stick with the DEPRECATED UML conjugation (not nested-port friendly) and await migration.

[ISSUE, TOOL] MagicDraw/Cameo v19SP3 vs SysML&SysPhS: The sample project for the Humidifier example uses DEPRECATED FlowPorts (and sets values directly on them in the StateMachines).

[ISSUE, MODELLING]{STRONG} SysPhS-1.1: Annex A.5: Humidifier: Use of UML-style direct Port conjugation not permitted since SysML-1.6, prefer ~InterfaceBlock type-based conjugation (example requires migration)

[CONVENTION, MODELLING, NAMING, TIP]{STRONG} Webel: If you must name your Ports or Pins, name them simply 'i', 'o', or 'io' 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.

Snippets (quotes/extracts)

[SysPhS-1.1] A.5 Humidifier: A.5.1 Introduction: This subannex gives a model of a room humidifier as an example of signal flows and state machines.