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Instances of Classes as Exchange Items [message #1833233]

Wed, 07 October 2020 07:55

Eclipse User

Is it possible in Capella to use classes to define interface types and implementations such as it is done with SysML interfaceBlocks?

I'll give an example. Bruce Douglass in his "Agile Systems Engineering" book exemplifies an interface with the following definition:

index.php/fa/39030/0/

PowerBusInterface is a block with properties just as the Classes in Capella. It is then used to specify instances with different values.

I would like to be able to use such definitions for mapping engineering values into ICDs such as ARINC429 labels on the physical level - and forcing conformance to a base class that specifies the label structure. Is it possible?

In Capella the use case would be:

-Define Class for a given interface type.
-Assign an instance of the Class which specifies the ExchangeItem (which necessarily conforms to Class)
-Assign ExchangeItem to Functional Exchange / Interfaces.

Attachment: 2020-10-07 08_41_48-Chapter-8---The-Handoff-to-Downstream-Engineeri_2016_Agile-Systems-Engineeri - P.png
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[Updated on: Wed, 07 October 2020 07:59] by Moderator

Re: Instances of Exchange Items [message #1833234 is a reply to message #1833233]

Wed, 07 October 2020 07:58

Eclipse User

Obs.: I know PVMT kind of works around this issue (such as the properties in the oil cooling example by Jim Daly on the Rolls Royce webinar) but there are some limitations on the specification of properties in PVMT such as the impossibility (as far as I know) to include lists of properties in a given element.

Re: Instances of Exchange Items [message #1833245 is a reply to message #1833234]

Wed, 07 October 2020 11:43

Eclipse User

Hello,
Did you already checked out the Help -> Thematic Highlights section of Capella Help?
There are two chapters that may interest you: Functional Analysis and Interface Engineering, and Interfaces and Data Modeling in Capella.

Re: Instances of Exchange Items [message #1833458 is a reply to message #1833245]

Tue, 13 October 2020 14:47

Eclipse User

Hi Juan,

I have checked these pages but haven't been able to find anything relatable to instancing classes or instancing exchange items in Capella.

Closest I have found was the "ComplexValue" which is a kind of Value typed by classes but it is not really user-friendly, it does not enforce compliance with the class (which would be the big gain on using classes to set a data type defintion).

This would be useful for general use of data objects in Capella but I see a specific application: Define Exchange instances which could be used to specify specific instances of functional interactions such as in Functional Chains and in Scenarios.

Example use case:

1-Open a CDB and define an Exchange Item with a list of Exchange Item Elements:
index.php/fa/39059/0/

2-Allocate Exchange Item to Functional Exchange 1
3-Create functional chain including Functional Exchange 1
4-Open Functional Chain Involviement Link (instance of Functional Exchange 1).
5-Define ExchangeItem1 as echanged element
6-Define an instance of ExchangeItem1 as Exchange Context of the Functional Chain Involvement Link, in the example:

ExchangeItem 1 instance:
ExchangeItemElement1:
-Property 1 = 10
-Property 2= 12304
ExchangeItemElement2: True

7-Display ExchangeItem 1 instance graphically on the diagram for clarity.

Attachment: ExchangeItem.png
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Re: Instances of Exchange Items [message #1833475 is a reply to message #1833458]

Wed, 14 October 2020 05:55

Eclipse User

Hello,

The use case you describe can be done with Scenarios today. Try the following:

1-Open a CDB and define an Exchange Item with a list of Exchange Item Elements, THE DATA TYPES AND THE VALUES (EX. ENUMERATION)
2-Allocate Exchange Item to Functional Exchange 1
3-Create SCENARIOS including Functional Exchange 1 (AS A MESSAGE)
4-Open SEQUENCE MESSAGE.
5-Define ExchangeItem1 as exchanged element
6-DEFINE THE EXCHANGE CONTEXT OF THE MESSAGE, USING EXISTING MODEL ELEMENTS (Ctrl+Space FOR AUTOCOMPLETION)

It would be relevant to do the same for Functional Chains indeed (not implemented today)

Hope it helps,

Re: Instances of Exchange Items [message #1833606 is a reply to message #1833475]

Mon, 19 October 2020 13:28

Eclipse User

Thanks for the response Juan!

That exact procedure is possible also with functional chains although the [display] "Exchange Context" accelerator for functional chain description diagrams is missing. I was able to around this but I had to load the exchange context in the diagram as a regular constraint. (functional chain involvement links also have the "Exchange Context" field so it is possible to create the constraint, the only thing missing is the accelerator to properly bring the representation to the diagram - with the "Constraints" accelerator I'm able to bring the constraint but without the proper link).

The difficulty I have is with defining the Exchange Item instance, I could use the ctrl-space to properly reference the ExchangeItem but I'm not able to specify the properties within the exchange item as an instance in the CDB so that I can reference the specific instance - notice, it is not a big issue for me, I just wanted to know if it was possible since there seemed to be provisions for that: I've noticed I can add an "Exchange Instance" on the Exchange Item in the Project Explorer but it does not enable me to specify properties based on the definition of the exchange item.

Thanks again for the time taken reading and answering this

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