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Items, Properties, and Values
Blocks of interest
As discussed in “Items and informational values” on page 102, items are what flow through the model, properties contain information about items, and values provide information about model conditions. This chapter discusses items and their properties and how information about them is reported as values. It will cover:
• Generating items randomly and by schedule
• The Create block’s Start connector
• Attributes,priorities,quantities,andotheritemproperties
☞ Most of the models illustrated in this chapter are located in the folder \Examples\Discrete Event\Items and Properties. For other models, location information is provided at the begin- ning of their respective discussions.
Blocks of interest
The following blocks will be the main focus of this chapter. The block’s library and category appear in parentheses after the block name.
Item generating and removing
Create (Item > Routing)
Creates items randomly, by schedule, or infinitely. Can also be used to create values
randomly or by schedule. Can initialize newly created items with properties, such as attributes or priorities.
Exit (Item > Routing)
Passes items out of the simulation. Reports the total number exited and the number that were taken from each input.
Item properties
Get (Item > Properties)
Displays the value of user-assigned and system level item properties: attributes, priori- ties, quantity, and item index.
Set (Item > Properties)
Attaches user-assigned properties (attribute, priority, and quantity) to items passing through.
Equation(I) (Item > Properties)
Can be used to set, modify, or check attributes on existing items. Calculates the equa- tion when the item arrives.
Its Item Attributes tab is used for attribute management, such as renaming or deleting attributes or locating where they are used in a model. It is also where string/value equiv- alents are declared for string attributes.
Discrete Event

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