Hi!

I am reading in Chapter 8 of Agile Systems Engineering, while simultaneously reviewing the example model TWrecks1.rpy and have some questions.

in ibCommCoord there are three flowProperties called

cmdProximalJointAngle:JointRadian
cmdMedialJointAngle:JointRadian
cmdDistalJointAngle:JointRadian

These are combined into the message CommandedJointAngleMsg:CANMsg with the following mapping:

Data0:unsigned char = Low byte Proximal Angle
Data1:unsigned char = High byte Proximal Angle
Data2:unsigned char = Low byte Medial Angle
Data3:unsigned char = High byte Medial Angle
Data4:unsigned char = Low byte Distal Angle
Data5:unsigned char = High byte Distal Angle

In paint it would look something like this:

Now to my questions:

1. Why are there no explicit relation between the logical flowProperties and the physical data? Wouldn't that kind of traceability be beneficial to know exactly how the logical data schema is refined into the physical? It feels unsatisfying on relying on the semantics of the text string to indicate traceability.

2. If I where to add such a relation how would I do it in the best way?

To I have tried to use «allocate» and «dependency», but that can only be done between the interface specification and the flow property and not to the exact value (Data0, Data1, ...). See below:

Thanks in advance!

Best regards

Markus