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Extend is a simulation tool to create models quickly, with all the blocks you need and without even having to type an equation.

You can use a series of simple block definitions to describe complex processes. Extend also provides an equation editor so you can combine the function of several blocks into one. You can even create your own libraries of custom blocks for specialized applications.

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1 - EXTEND

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A full array of building blocks that allow you to build models rapidly.

A customizable graphical interface showing the relationship in the system you are modeling.

The ability to adjust settings while the simulation is running.

Customizable reports for presentation and in-depth analysis.

Full connectivity and interactivity with other programs and networks.

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1.1 – What Extend Can Do

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Extend libraries hold blocks that you can use to create models.

Classical simulation is generally divided into continuous and discrete event. The Generic and Electronics libraries are used for continuous simulation. The discrete event libraries (Discrete Event and Manufacturing) are used for models that use queues, item-specific attributes, and priorities.

Other libraries are included as well.

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1.2 – Continuous and Discrete Event

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Model – Composed of components (called blocks) with connections between them

Library – Repository of blocks

(Turn on the PC ) Start the program: Start Programs Extend6 Extend6

Libraries are found by the Library menu item.

The most important parts of a model are the blocks, the libraries where the blocks are stored, the dialogs associated with each block, the connectors on each block, and the connections between the blocks.

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2 – RUNNING A MODEL

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A block specifies an action or a process.

A block in Extend is like a block in a block diagram. It is used to represent a portion of the model. Some blocks are a source of information, other modify information as it passes through them.

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2.1 – Blocks

Dialog

BlockInput

ConnectorsOutput Connectors

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The entire definition for a block is stored in the library.

When you include a block in a model, a reference to the block information in the library is included instead of copying actual blocks to the model.

When you open a model, Extend automatically opens the needed libraries.

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2.2 – Libraries

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Most blocks have a dialog associated with them. You use dialogs to enter values and settings before you run your simulations.

To open a block’s dialog, simply double-click on the block’s icon.

You can get more information about the block by clicking on the Help button. To the right of the Help button is a text entry box for typing a block label.

When you click on a button while the simulation is running, it pauses, and, after resuming, the block gets that changed valued on the next step.

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2.3 – Dialogs

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Most blocks in Extend have input and output connectors (usually pre-defined)

You use connecting lines (connections) to hook blocks together

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2.4 – Connectors and Connections

Value Connectors

Used to pass values (information)

Item Connectors

Used to pass entities (items)

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Continuous Simulation Lake Pollution Example

Discrete Event Bank Line Example

Open Examples Tutorials

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2.5 – See Built-In Examples

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New Model

Open the libraries

Add blocks to the model

Connect the right types of input with the right types of output. The behavior of most connectors is predefined. If the connection was not made correctly, the line will show as a dotted line instead as a solid line.

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3 – BUILDING A MODEL

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Continuous modeling is used to describe a smooth flow of homogeneous values; discrete event models track individual and unique entities.

In continuous models values change based directly on changes in time, and time changes in equal increments.

In discrete event models, simulate time advances from one event to the next and it is unlikely that the time between events will be equal.

You will often use blocks from different libraries within the same model.

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4 – CONTINUOUS AND DISCRETE EVENT MODELING

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The blocks in the generic library are useful for both quickly building continuous models, and for performing specialized tasks when connected to value connectors in discrete event models.

If you have connected an input and also enter a value for that input in the dialog, the connector’s value always overrides the value in the dialog.

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4.1 – Continuous Modeling

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In discrete event blocks, an item connector passes an item and all the information associated with it to the next item connector.

The Executive block must be to the left of all other blocks.

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4.2 – Discrete Event Modeling

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Items are individual entities that can have unique properties as specified by their attributes, priorities and values.

Values provide information about items and about model conditions.

Extend moves items in your model only when an event occurs. Events are occurrences and are controlled by the Executive block. Blocks that do not generate events allow the blocks after them to pull items during a single event.

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4.2.1 – Items and Values

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- Extend v6 User’s Guide

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BIBLIOGRAPHY