Astah SysML Tutorial

Parametric Diagram

Now let's move on to creating the Parametric Diagram below.

Parametric Diagram

From P.180 Figure.B.24 - Defining Fuel Flow Constraints (Parametric Diagram) of OMG SysML 1.2)

A parametric diagram is defined as a restricted form of the Internal Block Diagram. A Parametric Diagram may contain constraint properties and their parameter, along with other properties from within the Internal Block context.

Let's create a new Parameter Diagram by Right-clicking the "PowerSubSystem" Block and selecting [Add Parametric Diagram] from its Pop-up menu.

First, draw the Constraint Property which is a property of any Block that is typed by a Constraint Block. We need a Constraint Block to do that, so let's create one. Right-click on the root-topic and create a new Package to hold this Constraint Block from [Create Model] - [Add Package] and name it as "Constraints". Now create a new Constraint Block in this Package by right-clicking on it, then go to [Create Model] - [Add Constraint Block] and name it as "FuelFlow".

Parametric Diagram 2

A Constraint Block "FuelFlow" is created. Go to [Constraint] tab of its Property View and add the constraint from the Constraint field as shown below.

Parametric Diagram 3

Now drag the Constraint Block from the Structure Tree into the diagram editor and name it "fuelflow".

Parametric Diagram 4

Now Create the Value Properties that are shown in pink in the sample diagram. But before we do that, we need to create a few Blocks first. Let's quickly create a new Block Definition Diagram with the instruction below for you to practice!

Parametric Diagram 5

  1. Create a new Block Definition Diagram name it whatever you like
  2. In the Structure Tree, select [PowerSubSystem] and [InternalCombustionEngine] Blocks, then drag and drop them on the Block Definition Diagram
  3. Next create two more Blocks - FuelFlowRate and FuelDemand and create Compositions between them
  4. Let's add values to the "FuelFlowRate" and "FuelDemand" Blocks. To do so, select each Block and go to its Property View and open the [values] tab. Click [Add] button, and then name it "fuelDemand" and choose Type for "Real" from its dropdown list. Now let's do the same to "fuelFlowRate".
    Parametric Diagram 6
  5. Astah_another_Block_Definition_values

Now that you are all set, let's get back to the Parametric Diagram and create an "" Value Property. First select the Value Property from the tool bar and click on the diagram.

Parametric Diagram 7

When you click on a diagram, the following dialog appears.

Parametric Diagram 8

Select "fuelDemand:Real" and then click [OK]. Now create another Value Property in a same way you just did.

Now all you need to do is to add the Value Properties and the Constraint Parameter with Binding Connector to complete this Parametric Diagram. To connect them with BindingConnector, you need to add the "Constraint Parameter" to the Constraint Properties first.

Select the "Constraint Parameter" and add it to "fuelflow" Constraint Property and name them as shown in the sample diagram.

Parametric Diagram 8

Parametric Diagram 9

Now select "BindingConnector" and then connect each Value Type and the Constraint Property.

You have completed this Parametric Diagram.