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All figures in these simulations were generated using LabVIEW software. Front panels and VI diagrams were captured to "pict" files using the program "Pictify" and processed for display in Microsoft Word version 6 with Canvas 3.5. Only cosmetic changes were made in the diagrams and panels, and those only for teaching clarity. Permission has been obtainded from National Instruments, Austin Texas, (11/6/96, Ms. Roxanne Green, telephone), the copyright owner of LabVIEW and the Student Edition of LabVIEW, to use the LabVIEW illustrations in this work.
A particularly nice example of recent work comparing van Deemter plots for liquid and gas chromatography - Simulation 16.

example results


The Simulation Problems

The simulation problems that follow represent a new classroom activity that bridges between the lecture, the text, and the lab. They allow you to build virtual instruments that simulate critical parts of entire chemical instruments in a way that can only be approximated in a lab situation. With these virtual instruments, you can explore the criticality of key parameters. You can learn how a particular parameter effects the whole chain of events between an analytical sample and a final result. You can learn how some subtle aspect of an instrument actually works. And, you can add functionality to lab data. The simulations offer a unique opportunity for learning.

The simulations are intended to accompany the textbook that we will use for the 382/378 course.

There are 19 simulation problems. They were chosen based on those topics that are in the book, yet still have been difficult for previous classes to understand in a practical sense. Each problem has arisen from office discussions and tutorials, many with regard to fundamental principles, and others with regard to electrical or mechanical details of the instrument.

When the problems were written, it was with an eye to having significant learning about the instrument result from building the virtual instrument. Thus, while you could simply use the example instrument shown in the problem, it is far better to engage in building it.

The simulations are written with LabVIEW, version 6i. It is expected that you will purchase the LabVIEW 6i Student Edition manual (as shown here at the left) and software (which is included for both PC's and Mac's with the manual). It is expected that you will use this to build your own virtual instruments, using one or another of the Macintosh or PC computers available to us at St. Olaf.











Why learn LabVIEW? As you look ahead in your profession, you will discover that people who manage you will constantly expect more for less, and time spent on a project is one of the quantities for which much more will be expected for much less. This certainly has been true for NASA in attempting to convince Congress and the American public that it should offer a series of missions to Mars. What carried its arguments most was not the payoff, but rather the payout. Using a motto of "better, faster, cheaper", it dropped the Sojourner rover robot onto the surface of Mars, and did x-ray fluorescence analysis of key rocks. One way in which JPL scientists saved money was to use commercial software packages, rather than hiring a battery of programmers to work up their own proprietary code. One of those packages that was used to analyze the Martian temperature both inside and outside the rover robot was LabVIEW. In the figure above are shown those temperature data, conveniently displayed as a LabVIEW xy graph. You should learn LabVIEW so you can adapt to the devices and developments of your times, whatever they are!


 

These simulation problems were all written with the idea that a role-playing group of four people would work on them. There will be four roles, namely, Manager, Chemist, Hardware, and Software. The group will divide responsibilities (but not necessarily the work) according to the following guidelines.

Manager will have the responsibility for scheduling, coordinating, and guiding the others in the group as the problem is solved. Manager will decide how and where computers are to be used, how the labor will be divided, and will schedule all sessions where the group must meet in person. Manager will help with getting all the communication about scheduling, places, times, and group meetings underway, and will handle all of the e-mail between members of the group and also between Manager and Upper Management. Manager will be responsible for the content of the final report submitted to Upper Management and for making sure that all members of the group have either an electronic or paper copy of it.. Manager will get the grade for the simulation problem; all others in the group will get the same grade.

Chemist will have the responsibility for designing and for setting up the LabVIEW VI’s, including gathering all relevant data and formulas, and for designing the front panels of the VI. Chemist also will be responsible for providing any example data that will produce known answers or "standards" that Software will need to do technical accuracy checks for the running VI’s.

Hardware will have the responsibility for acquiring or preparing all computer art work for the front panels of the VI’s. Hardware also will be responsible for all laser printouts, color or black and white, for providing all computer supplies (disks, etc.), and for transferring all resources located on the Analytical Chemistry server to whomever Manager decides needs them.

Software will be responsible for wiring the VI, using Chemist’s design, Hardware’s front panel art work, and Manager’s timetable. Software will be responsible for verifying that the VI runs, or does not run, and interact with others in the group until the running model is complete. Software will then be responsible for distributing the running VI to all others in the group for inspection, operation, understanding, and/or modification.


 

Simulations are assigned on class days when textbook problem sets are not assigned. Generally, there are three to six days between the assigned day and the due day, depending on the expected difficulty of the simulation. Manager has to coordinate the work of the role-playing group so that work does not pile up or interfere with the completion of other course activities, and still is submitted, if electronically before midnight on the day that it is marked as due, if on paper during class on the day that it is due.

There are 19 simulations. The first three are to be done individually, assuring that all people in the group can handle LabVIEW. Following that, the remaining 16 will have role-rotations. In other words, a person in the group will be Manager four times during the semester, Chemist four times, Hardware four times, and Software four times. A detailed schedule with roles and rotations assigned according to the class schedule will be handed out in the first class.

Division of responsibility does not presuppose division of labor. For example, while Hardware is responsible for preparing or acquiring all of the front panel art work, this does not imply that the person who is playing the Hardware role cannot get help from someone else in the class or in the group. What it does mean is that Hardware will be responsible to Manager for making sure that the art work for the front panel is in the right place at the right time. Similar comments can be made about all of the other roles, except for Manager’s. Manager alone is responsible for the work of his or her group, and cannot delegate labor to that end to anyone else.

These simulation problems are intended as an educational experience. Each person in the group must have the opportunity to run the VI that the group prepares, and to understand what it does, what it teaches, and how it relates to the text and lab material for the course. Since the simulations will be covered on the class examinations, in kind if not degree, then it is ultimately Manager’s responsibility to see that each person in the group has the VI in time to prepare for the appropriate examination. Manager cannot force those in his or her group to use the completed VI. But he or she is responsible for assuring that each person has an adequate opportunity to do so.

Role assignments and rotations for a class of 12 students are shown in the following table. People assignments are made alphabetically at the start of each semester.

 

Student A

Student B

Student C

Student D

Student E

Student F

Student G

Student H

Student I

Student J

Student K

Student L

 

1

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

1

2

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

2

3

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

alone

3

4

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

4

5

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

5

6

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

6

7

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

7

8

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

8

9

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

9

10

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

10

11

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

11

12

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

12

13

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

13

14

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

14

15

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

15

16

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

16

17

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

17

18

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

18

19

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

Software

Manager

Chemist

Hardware

19


 

Listed below are the criteria that will be used for grading the simulations. Note that the first three simulation problems are to be done individually. The point total will be 200 for all 19 problems, with the additional 10 being awarded subjectively for the quality of your professional collaboration during the semester. Each Manager will start with a full 10 points for the simulation. The final grade will be set by making progressive reductions in this base score. Reductions follow in four categories.

1. Punctuality

The assigned and due dates for the simulations are given in the class calendar. The simulation is to be turned in, by Manager, electronically, on the day that it is due, any time before midnight. If this is met, then there is no penalty for punctuality.

a. 24 hours after due date = 50% reduction

b. 48 hours after due date = 70% reduction

c. More than 48 hours later = 80% reduction

2. Appearance

The final report turned in by Manager should have a crisp, professional appearance. Length is not at all an issue. The following features will be observed critically.

a. Spelling. 5 or more words misspelled = 30% reduction

b. Poor grammar and sentence structure = 20% reduction

c. Sloppy artwork on VI front panel = 20% reduction

d. Confusing layout on VI diagram = 10% reduction

3. Originality

Manager must attest to the following points.

a. The VI built from scratch and works = no reduction.

b. The VI taken from the server and partly modified and works = 25% reduction.

c. If the VI taken from the server and used as is = 50% reduction.

4. Technical Content

The VI must be used properly to meet the objectives of the simulation. The following apply.

a. All of the stated objectives explored and met = no reductions.

b. More than half of the objectives are met = 25% reduction

c. Less than half of the objectives met = 50% reduction

c. The Old College Try = 75% reduction

 

It is not necessary for Manager to gather the entire group together in one room to work on a set of computers all at one time. This is only one of the simpler methods of group management. Another way is to set up a series of scheduled e-mail exchanges. Another addition to the e-mail mode, since the Mac machines can run more than one window at a time, is to make sure that the people who are exchanging mail also have their file-sharing modes turned on. Then, when Manager or another in the group wants to share some of their work, the recipient and simply mount the donor’s machine on their desktop, open it, and drag the files of concern to their hard drive. This allows the group to send mail and simultaneously exchange the virtual instrument parts (such as Hardware’s art work) that they are working on.


 

E-mail becomes especially powerful when all the people in the group have their own computers and can be on the same network, in the same AppleTalk zone, at the same time. This is not true for all at St. Olaf yet, although the college is close. For example, many people in the class will reside in Manitau or Rand halls, where ethernet links are in each room. Also, many will have their own Macintosh computers.

Several other tools have been provided for the group in the "St. Olaf Software" server. In addition to Microsoft Word, versions 5 and 6, there also is a pair of programs that Hardware will find most useful for preparing the illustrations that Manager will need to insert into the final report.

These programs are "DeskDraw" and "DeskPaint". When Hardware has snipped a picture from the functioning VI, she or he will need to clean it up. This means cropping out the ragged edges, adding other pictures to make a composite, and possibly adding text and arrows to elaborate on some functions of the VI. Manager would consult on such tasks. To do this, DeskPaint can be used to hold the picture while erasures and other cosmetic changes are done, while text can be added with DeskDraw.

Tasks like the above are not difficult if Hardware’s intermediate work is all saved as "pict" files. This kind of file can be transferred between DeskDraw and DeskPaint via the clipboard, or saved and added when a new file is first opened.

Other resources on the server that may be of use are Excel 5 and MacDraw II.


One particularly useful resource for Hardware and Manager is the "Pictify" control panel shown below. This panel is available on the Analytical Chemistry server. It should be dragged into the control panels of the machine at which the VI is being built, and then the machine restarted to activate it. If you set the controls as shown in the figure, then you can press the shift-option key combination, and a small cross shaped cursor will appear on your screen. With the mouse button depressed, you can drag a "marquee" around any screen ../pix/Image that you want to capture and store as a file on your machine.

This file then can be loaded into DeskPaint or DeskDraw to be cleaned up, saved as a "pict" file, and later inserted into the final Microsoft Word document that Manager will hand in. All of the figures in this book of simulation problems were prepared this way. Another option is to drag the panel onto a floppy disk which you can then use to reload into any machine’s system folder. With System 7.1 or higher, the system will ask you if the program is to be put into the control panels folder. Answering yes and restarting the machine will activate the capture utility.

When the group is ready to hand in its work, Manager and Software should collaborate to make a document that contains snapshots of the VI’s, both typical front panels and diagrams, a needed. This is definitely a creative activity.

Software can operate Microsoft Word to "insert pictures" into a template diagram (see diagram at left as an example).

If Word version 6.0.1 is used, then it will be much easier for Manager to add text that will flow around the pictures. Manager’s text should explain how the group operated and what was accomplished in building and operating the VI in terms of the original simulation problem objectives. While a long report is not needed, there should be enough in it that when the members of the group keep a copy for themselves, to use in their professional portfolio, they will be clear about what was done, and how they all contributed to the final product. A portfolio like this may be effective in interview sessions.

When it is time to hand in the work, Manager can use one of three convenient routes.

• The easiest way is just to mount the Analytical Chemistry server on his or her desktop, and drag the work into the designated folder. A mail message can then be sent to Upper Management indicating that the work is at folder. Of course, this does usually mean that not all in the group get to see a paper copy of the work. So, while it is easiest, it is not necessarily the best way to prepare for examinations. Manager should keep this in mind.

• The next easiest way to hand in work is via the e-mail, using Eudora, by making the work an "attachment". This is better than dragging the work to a folder, since copies can be sent to each person in the group for their files and for exam preparation.

• The best way of all is for Hardware to make a printed copy for Manager to hand in, and for each person in the group to keep in their files and for exam preparation.


 

If the work is to be handed in electronically, as an attachment to a Eudora e-mail memo, then consider the following figure.

When Eudora is launched, and a new mail message is showing, you may pull down under the "Message" menu to the item called "Attach Document".

When you release the mouse button, you will be given a requester window that will allow searching out the document to be handed in. Then, releasing on its file name will automatically "attach" it to the memo.

The memo will be time/date stamped, and in it Manager can describe what is being attached, and add other comments as needed.

When Upper Management receives the mail, the attachment will automatically be decoded and deposited into a special folder for inspection and grading.

It always is Manager’s responsibility to see that all members of the group get an accurate copy of what is being handed in before they need it to study for the next examination, no matter which of the above three methods are used.

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