Create a flowsheet variable

Create a flowsheet variable from the Simulation Manager

1. In the Simulation Manager, right-click the Main branch, and then in the Add Variable submenu, select the variable type that you want to use for the flowsheet variable.

   The new flowsheet variable appears in the Simulation Manager, under the Main branch.

   The new flowsheet variable uses:

   • A default name.

   • The default value for the variable type that you used to create the flowsheet variable.

   • The default unit of measure (UOM) for the variable type that you used to create the flowsheet variable.

2. (Optional) Rename the flowsheet variable. See Rename a flowsheet parameter or a flowsheet variable for more information.

3. (Optional) Select the default value for the flowsheet variable, and then enter a new value.

4. (Optional) Select the default UOM for the flowsheet variable, and then in the resulting list of UOMs, select the UOM that you want to use for the flowsheet variable.

5. (Optional) Select the checkbox for the flowsheet variable to specify the variable value or clear the checkbox to calculate the variable value.

   Flowsheet variables are specified by default. If you choose to calculate the variable value, you must create a flowsheet equation to calculate the value. Otherwise, your simulation is improperly specified (unsquare). See Create a flowsheet equation on the Canvas for more information.

Create a flowsheet variable from the Tools Library

6. Drag a Variable from the Tools Library onto the Canvas.

   A new flowsheet variable appears in the Simulation Manager, a Variable Reference for the flowsheet variable appears on the Canvas, and the properties dialog for the flowsheet variable opens.

   Tip: If you inadvertently close the properties dialog, you can reopen it by right-clicking the Variable Reference on the Canvas or the flowsheet variable in the Simulation Manager and then selecting Variable Properties.

7. In the properties dialog for the flowsheet variable, in the Name box, enter the name that you want to use for the new flowsheet variable.

   The Variable Reference name updates to match the flowsheet variable name.

8. Select the dropdown arrow for the Type list, and then select the desired variable type.

   The value and UOM for the flowsheet variable update to match the default value and UOM for the selected variable type.

   The Variable Reference value and UOM also update to match the default value and UOM for the selected variable type. However, you can change the Variable Reference UOM independently of the UOM for the flowsheet variable. Also, deleting the Variable Reference does not affect the flowsheet variable.

9. Do one of the following to close the properties dialog:

   • Select x on the dialog.

   • Select anywhere on the user interface outside of the dialog.

10. (Optional) Do one of the following to update the value for the flowsheet variable:

    • In the Simulation Manager, locate the flowsheet variable, select its value, and then enter the new value.

    • On a Variable Reference for the flowsheet variable, select the value, and then enter the new value.

11. (Optional) Change the UOM for the flowsheet variable by doing the following:

    1. In the Simulation Manager, locate the flowsheet variable.

    2. Select the UOM for the flowsheet variable.

       A list of available UOMs appears.

    3. In the list of UOMs, select the UOM that you want to use for the flowsheet variable.

    Integer parameters do not include a UOM.

12. (Optional) Do one of the following to change the specification status for the flowsheet variable:

    • In the Simulation Manager, locate the flowsheet variable, and then select its checkbox to specify the variable value or clear the checkbox to calculate the variable value.

    • On a Variable Reference for the flowsheet variable, select its checkbox to specify the variable value or clear the checkbox to calculate the variable value.

    Flowsheet variables are specified by default. If you choose to calculate the variable value, you must create a flowsheet equation to calculate the value. Otherwise, your simulation is improperly specified (unsquare). See Create a flowsheet equation on the Canvas for more information.