Declare model data items

Declaring data items defines:

the name,
data type,
dimensional units type,
default value,
bounds and
description of data items.

Declaring data items allocates memory for storing data values and assures that the values are saved when the model file is saved and recalled when the model is opened. Data items are declared in the Composite Model and they are initialized in the Case model which runs the composite item.

To add Data Items

Open the Two-Stage Flash composite model. Select View | Method.
Right click in the Model Window and select Properties. The Properties dialog is displayed.
Select the Data Sets tab. The data set Equipment Properties has been defined.

Add a Data Item by selecting the Data Set and clicking the Data Item New button .
Enter the Data Item name First Stage Pressure. The Data Item name must be unique to the Data Set.
Press the Enter key when done.
Select Method Item Reference for the Data Type. Select First_Stage_Flash for the Method Item.
Select Flash Pressure for the Data Item.
Enter First Stage flash pressure for the Data Item Description.
The above declares a Data Item which is a reference to the first stage Flash's Flash Pressure Data Item.

Click the Data Items New button. Enter Second Stage Pressure for the Data Item name and press the Enter key.
Select Method Item Reference for the Data Type. Select Second_Stage_Flash for the Method Item.
Select Flash Pressure for the Data Item.
Enter Second Stage flash pressure for the Data Item Description.
The above declares a Data Item which is a reference to the second stage Flash's Flash Pressure Data Item.

Press OK. Save the Two-Stage_Flash Composite Model.
Double click the Two-Stage_Flash item in the Two_Stage_Flash Case Model. The Data Set and Data Items are shown for the Two-Stage_Flash Composite Model.