Arena Tutorial.pdf

Arena

Tutorial

This Arena

tutorial aims to provide a minimum but sufficient guide for a beginner to get

started with Arena

. For more details, the reader is referred to the Arena user’s guide, which

can be found in Arena program (Help >Product Manuals>Arena User’s Guide).

1. Installation

You can download the student version of Arena software from the link below:

http://arenasimulation.com/downloadarena

To proceed with the download, you have to register your account with your valid email

address. Once registered, you can log into the download site and follow the download

instructions provided at that site. During the installation, customer information will be asked

to enter with the serial number. In that case, you have to enter STUDENT in the serial

number field as shown below.

2. Overall Features of Arena

2.1 Arena Window Structure

You can run Arena from the Window Start menu and navigate to Program > Rockwell

Software > Arena. If a warning message will prompt, click OK to go on. The Arena will bring

you the new modeling environment as follows:

In the Arena window, you will face with the three regions where you’ll work for building a

simulation model.

1) Model Window (Flowchart view)

The flowchart view is a canvas to draw the process flow of entities using modules

from the project bar. It can also have the animation and other drawing elements

2) Model Window (Spreadsheet view)

The spreadsheet view displays the properties of selected module in the flowchart

view or the project bar.

3) Project bar

The project bar holds some panels that provide the various objects so as to help you

build the simulation model and reports

 Basic Process panel: holds modeling commands called modules that are

used to model your system.

 Reports panel: provides a road map to the results of a simulation run

 Navigate panel: allows to display different view of a model

The Arena also provides additional panels that provide various types of objects such

as advanced process, advanced transfer panels and so on. In order to use these panels,

you need to attach a panel located in Arena’s template folder by selecting a panel file

(ends with “tpo” extension) from File > Template Panel > Attach. In reverse, if you

don’t need it any more, you can detach from the project bar from File > Template

Panel > Detach.

2.2 Modules

In Arena, modules are basic building blocks (or objects) that consist of Arena models. There

are two types of modules: flowchart modules and data modules. All the modules can be found

in the project bar.

1) Flowchart Modules:

The flowchart modules are used to describe the flow of entities and placed in the

flowchart view of the model window.

In the Basic Process panel, you can find the following flowchart modules:

Name

Description

Create

Entities enter the simulation here.

Dispose

Entities are removed from the simulation here.

Process

An activity, usually performed by one or more resources and requiring

some time to complete.

Decide

A branch in entity flow. Only one branch is taken.

Batch

Collect a number of entities before they can continue processing

Separate

Duplicate entities for concurrent or parallel processing, or separating a

previously established batch of entities

Assign

Change the value of some parameter (during the simulation), such as

the entity’s type or model variable.

Record

Collect a statistic, such as an entity counter or cycle time.

2) Data Modules:

The data modules are used to define parameters associated with elements of the

model, such as resources, entities, queues and so on. The data module can be

accessed from the project bar by double-clicking a module and it will be shown on

the spreadsheet view of the model window.

In the Basic Process panel, you can find the following data modules:

Name

Description

Entity

Define the various entity types and their initial picture values in a

simulation. Costing information is also defined for the entity.

Resource

Define the resources in the system including costing information

and resource availability.

Queue

Define the queues in the system

Schedule

With the Resource module, define an operating schedule for a

resource or with the Create module, define an arrival schedule.

Set

Define various types of sets, including resource, counter, tally, and

entity type and entity picture.

Attribute

Define the entity’s attributes which consist of type, dimensions and

initial value.

Variable

Define the variables used through the modules in the model.

3. Building Models with Arena

Throughout this section, the process of building an Arena model of a single server system

will be explained with the details.

3.1 Reference Model (Single Server System)

during the simulation.

the

initial

picture

“Picture.Box”

which

will

used

animate

the

entity

flow

spreadsheet

view

to define a new entity.

Enter the

entity type with

“Job”

and change

Basic

Process

panel

the

project

bar,

click

the

Entity

module.

Double-click

the

Entity module:1)

Resource data modules.

Before modeling the flow of the entity, the entities and resources are defined using Entity

and

3.2 Defining each Data Module

Activity: service time

~ triangular (1, 3, 6)4)

Passive Resource: Buffer (unlimited)3)

Active

Resource:

Machine2)

Entity: Job arrives every

minutes (ta ~

Exp(5))1)

2) Resource module:

In Basic Process panel of the project bar, click the Resource module. Double-click

the spreadsheet view to define a new resource. Enter the name with “Machine”.

3.3 Constructing a Flowchart Model

In Arena, the flowchart represents the flow of entity in the system. In the single server system,

the entity, a job, 1) enters the system and waits in the queue. 2) The job will be processed by

the machine when the machine becomes idle. 3) The processed job will leave the system.

1) Create jobs

The starting point of the flowchart is always the Create module. Drag the Create

module from the Basic Process panel into the flowchart view of the model window.

2) Process jobs

Drag the Process module from the Basic Process panel into the flowchart view,

placing it to the right of the “Create 1” module. If the “Create 1” module is selected

before dragging, the connection will be automatically established from “Create 1” to

Process module. For this, check Object > Auto-Connect menu is activated.

If the connection is not made, click the Object > Connect menu or the Connect

toolbar button ( ) to draw a connection manually. Start the connection by clicking

the exit point (►) of the Create module, and then click the entry point (■) of the

Process module to complete the connection.

3) Dispose jobs

Select the “Process 1” module and Drag the Dispose module from the Basic Process

panel into the flowchart view, placing it to the right of the “Process 1” module.

3.4 Defining each Flowchart Module

1) Create Module

Double-click the “Create 1” module to open a dialog box so as to edit its properties.

(1) Type “Create a job” in the Name field.

(2) Select or type “Job” to name the entities in the Entity Type field.

(3) Type “5” in the Value field of the Time Between Arrivals section and select

“Minutes” in the Units field

(4) Click OK to close the dialog box.

2) Process Module

Next is the “Process 1” module. In this module, the behavior or flow of an entity at

buffer and machine will be defined. The newly created job waits at the buffer until the

resource (machine) becomes idle. If there is an idle resource, the entity seizes the

resource and holds for a time delay (representing resource’s processing of the entity),

and then it releases the resource for next processing of the entity.

Double-click the “Process 1” module to open a dialog box so as to edit its properties.

(1) Type “Process a Job” in the Name field.

(2) Select “Seize Delay Release” in the Action field of the Logic section.

Action field defines the behavior of an entity in this module.

- Seize Delay Release: the arriving entity seizes some number of units of a

resource, then is delayed for a time, and then releases the resource

- Delay: the arriving entity is simply delayed for some time and no resource is

required

- Seize Delay: seizes the resource and then is delayed, but does not release the

resource

- Delay Release: assuming that the resource is seized previously, the entity is

delayed and then the resource is released

(3) Click “Add...” button in the Resources filed of the Logic section to add a resource

for this module. The dialog box for Resources will be opened. Select “Machine”

in the Resource Name field. Click OK button to close the Resources dialog box.

Resources field defines the resources to be seized or released. It can be a

Resource or Set (a set of resources). The Quantity field indicates the number of

resources to be seized or released.

(4) To specify the time delay (service time) that follows the triangular distribution of

(1, 3, 6), select “Triangular” in the Delay Type field and type 1, 3 and 6 in

Minimum, Value (Most Likely), and Maximum fields, respectively. Also select

“Minutes” in the Units field.

The time delay for the Process module can be Constant, Normal, Triangular,

Uniform, and Expression.

3) Dispose Module

This module represents the ending point of the entity’s flow in the model. Nothing

special is mentioned here.

4. Running Simulation with Arena

4.1 Setting the run conditions

Prior to run the model, you need to specify the run conditions including project information

and the length of the simulation run. This is done in Run Setup dialog box from Run > Setup

menu.

1) Project Parameters

In Run Setup dialog box, select Project Parameters tab to specify the general project

information with Project Title, Analyst Name, and Project Description. You can also

specify for which categories you would like to collect statistics during the simulation

in the Statistics Collection field. Here, check the boxes of Queues, Entities, Processes,

and Resources of the Statistics Collection field.

2) Replication Parameters

In Run Setup dialog box, select Replication Parameters tab to specify how many

times the simulation runs and how long each simulation runs.

- Number of Replications: defines numbers of simulation runs to execute. Here,

type 1.

- Replication Length: defines the length of a single replication in a specified

time unit. Here, type 8 and select Hours in its Time Units (directly to the right

of Replication Length)

- Base Time Unit: defines time units for reporting, status bar, simulation time

and animated plots. All time delays, replication length will be converted to

this base time unit. Here, select Hours.

4.2 Running a simulation

You can start the simulation run simply by clicking the Go ( ) button in the standard toolbar

or clicking the Run > Go menu. If you have a valid model, then Arena continues to run the

simulation. If your model is not valid, Arena lets you know that with error messages.

Once the simulation starts to run, some animation will be displayed as the simulation

progresses. As shown in the following figure, entities in a box shape (as specified in Entity

data module) move from one module to another. Below the each module, number of entities

created, in processing, and disposed are displayed. At the top of the Process module,

displayed is the status of the queue of the resource (number of waiting entities) with entity

pictures. In this figure, there are four entities in Process module, among them, one entity is

actually being processed by the resource and three entities are waiting at the queue.

If you don’t want to see the animation anymore during the simulation run, click the Fast

Forward ( ) button to run the simulation as fast as possible without animation update. Also

you can start the simulation run via the Run > Fast-Forward menu.

4.3 Reviewing the output reports

At the end of the simulation run, a message box will prompt to ask you whether you would

like to view the reports. Clicking Yes displays the reports as shown below.

In the Reports panel, you can see the list of reports provided by Arena. By clicking one of

them, you can see the corresponding report. The above figure shows the Category by

Replication report which provides the output results for each replication. As we specified in

Run Setup > Project Parameter, statistics are collected in four categories (Entity, Process,

Queue, and Resource) in addition to the system category (default statistics collected by

Arena).

The statistics provided in Arena’s reports can be classified into three types of statistics:

 Tally statistics: it refers to the statistics such as average, minimum, or maximum of a

series of numbers. For example, the average and maximum of the total time in the

system of entities are 0.1145 hour and 0.3123 hour, respectively.

 Time-persistent statistics: it refers the statistics such as time average, minimum, or

maximum of a plot of something during the simulation run. The time average is the

accumulated area under the plotted curve divided by the simulation length. For

example, one of time-persistent statistics is the average of the number of entities in

the queue at the machine that can be found in the Queue  Other  Number Waiting

of the report tree located to the left of the report. Also, the instantaneous utilization of

the resource (Resource  Usage  Instantaneous Utilization) is one of the time-

persistent statistics.

 Counter statistics: it refers to the statistics of accumulated sum of something. One of

the counter statistics is the number of entities that entered or left the system which

can be found in Entity  Other  Number In or Number Out of the report tree.

According to the figure above, ninety jobs entered the system and eighty-nine of them

left the system.