Webel Radio Net: 'exchange' SysML Package Diagram with Signals (and Port types)

Gallery
Tutorial
[TRAIL] SysMLv1: The Webel Radio Net port-based messaging example model in Cameo Systems Modeler and Cameo Simulation Toolkit
Section
Webel Radio Net: Model overview, exchange items, and Ports
Topic level
BASIC
UML keywords
Signal
Keywords
Slide kind
SysML Package Diagram
It's a very good idea to identify exchange items early on:
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).
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Note this convention:

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.

With simpler projects, it is convenient to include any InterfaceBlocks that have exchange items as flows in the same Package (or Model package); for a project leveraging a formal Systems Engineering (SE) methodology, it's usually best to collect them in a separate Package called 'flow(s)' or 'interface(s)'.

For the Webel Radio Net model it was decided to use Signals throughout as the exchange items. Note that:

SysMLv1: CAUTION: Only a Signal can be used for a SendSignalAction or MessageEvent trigger of an AcceptEventAction, not a Block or ValueType, even if they are valid types for a SysML FlowProperty! But you can "wrap" a Block or ValueType in a Signal.

It could be argued that using the "packet" wrapping approach would be a more realistic fit for the Radio Signal and the RadioMessage family of exchange items, but it makes the modelling more complicated.

The 'exchange' Package Diagram also shows the additional SignalKind SysML Enumeration families used by the console diagnostic echo operations. The SignalKindS (corresponding to scheduling message Signals) and SignalKindR (corresponding to radio message Signals) both extend the abstract SignalKind, which acts as the main input parameter to the shared echo Operations. As noted in the introduction, these represent a slight maintenance overhead but are worth the extra effort for this Signal/Message-intensive Radio Net task.

Up next
Webel Radio Net: 'scheduling' SysML Package Diagram with scheduling message Signal families (and Port types)
Notes
[ASSERTION, MODELLING, PATTERN]{STRONG} 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).
[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.
[COMPLICATION, GOTCHA, LIMITATION, MODELLING]{INFORMATIVE} SysMLv1: CAUTION: Only a Signal can be used for a SendSignalAction or MessageEvent trigger of an AcceptEventAction, not a Block or ValueType, even if they are valid types for a SysML FlowProperty! But you can "wrap" a Block or ValueType in a Signal.
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