Variable

Then the manipulated

Variable is

Direct Increases Increased

Direct Decreases Decreased

Reverse Increases Decreased

Reverse Decreases Increased

Getting Started Guide Tutorial 2 - Modifying the Control Scheme  2-15

To modify properties for the newly-created controller block

MCHCOMP:

1. In the Process Flowsheet window, click MCHCOMP to select it.

2. Click with the right mouse button on the block.

3. From the menu that appears, point to Forms then Configure.

The Configure dialog box appears.

Aspen Dynamics has set default values for the controller gain

(1 %/%), integral time (20 minutes) and derivative time (0

minutes). Aspen Dynamics can also automatically initialize the

values for the operator set point, bias, the process variable

range and the controller output range. You can also manually

change any of these parameter default values.

You will now initialize the values of the controller properties:

4. On the Tuning tab of the Configure dialog box, click the

Initialize Values button.

Initializing Controller

Values

2-16  Tutorial 2 - Modifying the Control Scheme Getting Started Guide

The value for the operator set point changes to the steady-state

value for the MCH mole composition in the distillate stream.

The value for bias changes to the steady-state value of the

phenol solvent stream flow. These values are also used to

determine default values for the process variable and output

ranges, so that the current value is at 50% of range.

5. The MCHCOMP controller should be reverse acting, so

change the controller action. Under Controller Action, select

Reverse.

In this section, to improve the performance of this controller, you

will specify values for the operator set point, the gain, and the

integral time. You will also modify the controller process variable

and output ranges on the Ranges tab.

1. On the Tuning tab, in the Operator set point box, type 0.98.

2. In the Gain box, type a gain of 6.

Specifying Tuning

Values

Getting Started Guide Tutorial 2 - Modifying the Control Scheme  2-17

3. In the Integral time box, type an integral time of 30 minutes.

The Tuning tab now looks like this:

To modify the ranges for the process variable (measured variable)

and controller output (manipulated variable):

1. Click the Ranges tab.

2. Under Process Variable, in the Range minimum box, type 0.9.

3. Under Process Variable, in the Range maximum box, type 1.

Modifying Ranges for

Variables

2-18  Tutorial 2 - Modifying the Control Scheme Getting Started Guide

4. Leave the Output Range values unchanged.

The Ranges tab now looks like this:

You have now completed the controller specifications.

5. Click the Close button to close the Configure dialog box.

To incorporate a dead time for the measured variable:

1. In the Process Flowsheet window, click the MCHCOMPDT

block.

2. Click the right mouse button on the block and from the menu

that appears, point to Forms, then Configure.

The Configure table appears.

3. In the Configure table that appears, click the Value cell and

type 5 to simulate a sensor dead time of 5 minutes.

The MCHCOMPDT PID control block configure table looks

like this:

You have now completed the specification for the dead time

block.

4. Close the Configure table.

Modifying Dead Time

Block Properties

Getting Started Guide Tutorial 2 - Modifying the Control Scheme  2-19

Saving the Aspen Dynamics File

To save your changes to the Aspen Dynamics file:

➤ From the File menu, click Save.

The Simulation Messages window shows the file name and the

directory in which it has been saved.

Continuing with the Next Tutorial

You have now entered all the necessary information for the newly

created MCHCOMP controller block.

Now start the next tutorial.

. or .

To quit Aspen Dynamics:

➤ From the File menu, click Exit.

Getting Started Guide Tutorial 3 - Running the Dynamic Simulation  3-1

Associated manuals

Where to find further information

About This Manual

This manual contains three tutorials for you to work through, to

familiarize yourself with Aspen Dynamics

Associated Manuals

Aspen Dynamics also comes with these other manuals:

Manual Title Description

Using Aspen Dynamics Contains introductory information on Aspen

Dynamics, as well as instructions for

creating, editing and running simulations.

Reference Manual Describes the models, physical property

procedures and global parameters that are

available in Aspen Dynamics

Examples Manual Contains a series of worked simulations that

run in Aspen Dynamics

Using Aspen Traflow

(this may not be available

to you)

Explains how to use the pipeline flow model

Aspen Traflow.

ii  Introduction Getting Started Guide

What You Need To Use This Manual

To use this manual, you need Aspen Dynamics installed on your

PC or a PC file server running Windows 2000 or Windows NT.

For information on how to do this, read the AES Installation Guide

supplied with the product, or contact your system administrator.

For More Information

You can obtain information on AES products by:

Accessing the comprehensive online Help system

Reading the printed manuals supplied with your product

Printing the Portable Document Format (PDF) files supplied on

the installation CD

Accessing Aspen Technology’s web page

If you need more detailed assistance than that provided in the

online Help and the PDF files, you can contact Technical Support.

This section explains how to use the online help, print PDF files,

find Aspen Technology on the web, and contact Technical Support.

To access online Help:

From the Help menu, click Help Topics and then do one of the

following:

To Do this

Display a hierarchy of topics by

category

Click the Contents tab

Display an index of all Help topics Click the Index tab and then type

the word you require

Search for words or phrases within

the Help topics

Click the Find tab and then type

the word or phrase you require

Tip To display Help on buttons, fields, menu commands, and

other screen elements, click the What’s This button: or , at the

top of the window, and then click the element.

Printing Online Help

To display information on how to print online Help:

1. Open your Aspen Dynamics product and from the Help menu,

click Help Topics.

2. On the Contents tab, double-click Using Help and then

double-click Print Help Topics.

Online Help

Getting Started Guide Introduction  iii

To print these manuals, you must have Adobe Acrobat Reader

installed on your machine.

Tip If you do not have the Adobe Acrobat Reader, you can

download a free copy from the Adobe web site at

http://www.adobe.com.

Note Adobe and Acrobat are trademarks of Adobe Systems,

Incorporated.

After you have installed the Adobe Acrobat Reader, you can open

the files to view and print the manuals. To do this:

From the Start menu, point to Programs, then AspenTech,

Aspen Engineering Suite, Product Name 11.1, Documentation,

and then click the name of the manual you want to access.

For additional information about AspenTech products and services,

check the AspenTech World Wide Web home page on the Internet

at:

http://www.aspentech.com/

AspenTech customers with a valid license and software

maintenance agreement can register to access the Online Technical

Support Center at http://support.aspentech.com.

This web support site allows you to:

Access current product documentation

Search for tech tips, solutions and frequently asked questions

(FAQs)

Search for and download application examples

Search for and download service packs and product updates

Submit and track technical issues

Search for and review known limitations

Send suggestions

Registered users can also subscribe to our Technical Support e-

Bulletins. These e-Bulletins are used to proactively alert users to

important technical support information such as:

Technical advisories

Product updates

Service Pack announcements

Product release announcements

Printing the Portable

Document Format

Files (PDFs)