Humidifier Example

Blocks

In SysML, using SysPhS, the core humidifier components are represented by Blocks. For this example, where we are creating a StateMachine simulation, the focus is on the 'Control' Block. The Block Definition diagram (BDD) called 'Humidifier Components', which includes the 'Control' Block, is only one in a list of BDDs defining the humidifier.

The 'Control' Block has the StateMachine 'ControlStateMachine' as a Composite diagram under it; this is illustrated in the first diagram in the Overview section at the start of this topic.

The 'Control' Block is where Ports and a PhS constant for the humidifier control are defined. The Ports are of type RealInSignal, which are signal flows.

Common Types

As a starter for all SysPhS models, you need to ensure that the SysPhS common types are loaded in the repository, and referenced in the new model using the Package 'Import' connector. For more information see the Referencing SysPhS Libraries Help topic.

Phs Ports

The Value Types used for the Ports are pre-defined in the SysPhS Simulation Libraries. The key type used is the RealInSignal ValueType (RealInSignalElement). This can be dragged onto the Block as a Port and then renamed.

As an example of setting a Port on the Block, in this case the fanPowerOut Port, you drag a RealInSignalElement onto the Block and define it as a Port.

Note:

• These Ports can be set to both Modelica and Simulink by adding the stereotype for the other Port-type

Creating the StateMachine

To define a StateMachine as a Composite child-diagram to the Block:

• Select 'New Child Diagram > StateMachine' from the context menu on the Block, then
• Select 'New Child Diagram > Select Composite' from the context menu on the Block, and then select the diagram just created

Creating the States and Transitions

In the child StateMachine diagram, you add the Initial element, four States and a Final element. Then name these appropriately.

Note: By pressing the Spacebar when the diagram is selected, you can select an Initial object from the context menu, and then use the Quick Linker to add the remaining objects.

Transition Guards

The Transitions between the States contain conditions in their Guards. These conditions are defined in the Properties window 'Constraints' tab.

The variables used are the 'Control' Block's Phs constant and Ports. See the image in the earlier Blocks row.

Behaviors

Each State contains a script defining the mode and status of the fan. These scripts are set in the 'Entry' operation.

To edit the script for this, select the root StateMachine and pressing Alt+7.

Create a SysMLSimConfiguration Artifact

• Open the Block Definition diagram
• Click on the open space in the diagram
• Press the Spacebar
• From the 'Artifacts' sub-menu, select 'SysMLSim Configuration'
  This creates a new SysMLSim Configuration Artifact

Set the Package

• Double-click on the SysMLSim Configuration Artifact
  This opens the Configure SysML Simulation window
• In the 'Package' field, click on the [...] button and select the Package containing the SysML diagram

Set Modelica or Simulink

In the top drop-down, select which simulation tool to use:

• Modelica

• Simulink

For more details on these settings, see the Configure SysML Simulation Help topic.

Set the Block to Simulate

• In the left-hand list, under 'Block' in the 'Name' column, find 'HumidifierSystem'
• In the 'Value' column, click on the drop-down arrow and select 'SysMLSimModel'
  

Select Properties to Plot

You can now select the properties to be plotted:

• In the right-hand pane, select the Ports to plot