Vernier Spectro Pro User Manual
Spectro Pro
User’s Manual
Version 1.0
COPYRIGHT © 2001
Tufts University and Vernier Software & Technology
ISBN: 1-929075-15-4
07/15/01
Distributed by
Vernier Software & Technology
13979 SW Millikan Way
Beaverton, Oregon 97005-2886
(503) 277-2299
FAX (503) 277-2440
www.vernier.com
2 Spectro Pro
Spectro Pro
Short Table of Contents
SPECTRO PRO OVERVIEW ................................................................................................................................9
RO
PECTRO
S
HOW TO.................................................................................................................................................................15
P
UICK START
Q
..................................................................................................................................11
HANGE GRAPH APPEARANCE
C
ONFIGURE DATA COLLECTION OPTIONS
C
IEW OTHER WINDOW TYPES
V
NALYZE DATA
A
ERFORM DATA TABLE FUNCTIONS
P
AVE AND PRINT DATA
S
....................................................................................................................................................20
..............................................................................................................................15
..............................................................................................................17
...............................................................................................................................19
......................................................................................................................23
.........................................................................................................................................27
TEACHER’S GUIDE.............................................................................................................................................29
OFTWARE INSTALLATION
S
DEAS FOR USING SPECTRO
I
.....................................................................................................................................29
RO
IN THE CLASSROOM
P
..............................................................................................31
SPECTRO PRO REFERENCE.............................................................................................................................33
EYSTROKE EQUIVALENTS
K
OOLBAR
T
URSOR CONTROLS
C
PECTRO
S
..............................................................................................................................................................33
...............................................................................................................................................34
RO
ENUS
P
M
...................................................................................................................................33
............................................................................................................................................36
APPENDIX A TROUBLESHOOTING GUIDE................................................................................................61
APPENDIX B USING SPECTRO PRO ON A NETWORK............................................................................. 65
APPENDIX C INTERFACES COMPATIBLE WITH SPECTRO PRO........................................................67
APPENDIX D VERNIER SENSORS..................................................................................................................69
ENSOR PRICE LIST
S
...............................................................................................................................................70
Spectro Pro 3
4 Spectro Pro
Spectro Pro
Full Table of Contents
SPECTRO PRO OVERVIEW ................................................................................................................................9
Overview............................................................................................................................................................ 9
RO
PECTRO
S
Purpose............................................................................................................................................................ 11
Install software................................................................................................................................................ 11
Attach spectrophotometer ...............................................................................................................................11
USB connection...............................................................................................................................................12
Start up spectro Pro ........................................................................................................................................12
Collect data .....................................................................................................................................................13
Adjust graph ....................................................................................................................................................13
If you need more.............................................................................................................................................. 13
HOW TO.................................................................................................................................................................15
P
UICK START
Q
..................................................................................................................................11
HANGE GRAPH APPEARANCE
C
..............................................................................................................................15
Change axis limits manually ...........................................................................................................................15
Change axis limits automatically .................................................................................................................... 15
Zoom in on a graph ......................................................................................................................................... 15
Scroll to a new portion of graph without rescaling.........................................................................................16
Change what is plotted.................................................................................................................................... 16
Change other graph options............................................................................................................................16
ATA COLLECTION OPTIONS
D
.................................................................................................................................17
Set sampling speed (data collection rate) ...................................................................................................... 18
Set experiment length ...................................................................................................................................... 18
Sort data .......................................................................................................................................................... 18
IEW OTHER WINDOW TYPES
V
...............................................................................................................................19
Graph...............................................................................................................................................................19
Table................................................................................................................................................................19
Text..................................................................................................................................................................19
Meter ...............................................................................................................................................................19
NALYZE DATA
A
....................................................................................................................................................20
Read values from cursor..................................................................................................................................20
Read delta values between two points.............................................................................................................20
Read values from graph ..................................................................................................................................20
Display tangent lines....................................................................................................................................... 20
Compare runs.................................................................................................................................................. 20
Fit a line to data (linear regression)...............................................................................................................20
Interpolate between points .............................................................................................................................. 20
Fit functions to data ........................................................................................................................................21
Manual Fit (Model Data)................................................................................................................................ 21
Change Displayed Precision of Fit Parameters..............................................................................................22
ERFORM DATA TABLE FUNCTIONS
P
......................................................................................................................23
Change what runs appear in the data table....................................................................................................23
Change a column’s name, color, width, or digits displayed........................................................................... 24
Calculate new values from raw data (new columns).......................................................................................24
Enter data manually........................................................................................................................................26
Copy data to a spreadsheet or graphing program..........................................................................................26
AVE AND PRINT DATA
S
.........................................................................................................................................27
Save data, calibration and configuration........................................................................................................27
Paste data into other applications ..................................................................................................................27
5 Spectro Pro
Retrieve an experiment.................................................................................................................................... 27
Print a graph or data table .............................................................................................................................27
Print the screen ............................................................................................................................................... 27
Set default file locations..................................................................................................................................27
TEACHER’S GUIDE ............................................................................................................................................29
OFTWARE INSTALLATION
S
.....................................................................................................................................29
Required materials..........................................................................................................................................29
Initial setup......................................................................................................................................................29
Software installation Macintosh ..................................................................................................................... 30
Software installation Windows........................................................................................................................ 30
Software installation (network).......................................................................................................................30
RO
DEAS FOR USING SPECTRO
I
IN THE CLASSROOM
P
..............................................................................................31
Experiment files are important!...................................................................................................................... 31
Experiment files included with Spectro Pro....................................................................................................31
Protecting experiment files ............................................................................................................................. 31
Creating an experiment file.............................................................................................................................32
Customizing Spectro Pro................................................................................................................................. 32
Using Spectro Pro on a network..................................................................................................................... 32
Using Spectro Pro on stand-alone computers ...............................................................................................32
SPECTRO PRO REFERENCE ............................................................................................................................ 33
EYSTROKE EQUIVALENTS
K
OOLBAR
T
URSOR CONTROLS
C
..............................................................................................................................................................33
...............................................................................................................................................34
...................................................................................................................................33
Graph Window.................................................................................................................................................34
Graph title.......................................................................................................................................................34
Tick mark labels.............................................................................................................................................. 34
Axis labels ....................................................................................................................................................... 34
Scroll arrows................................................................................................................................................... 34
Axes .................................................................................................................................................................34
Graph options.................................................................................................................................................. 35
Selecting a graph............................................................................................................................................. 35
Table Window.................................................................................................................................................. 35
Select All/None................................................................................................................................................ 35
Column properties...........................................................................................................................................35
Column options ............................................................................................................................................... 35
Column order .................................................................................................................................................. 35
Edit cell contents............................................................................................................................................. 35
Strikethrough Rows......................................................................................................................................... 35
RO
PECTRO
S
ENUS
P
M
...........................................................................................................................................36
Apple menu...................................................................................................................................................... 36
File menu.........................................................................................................................................................36
Edit menu......................................................................................................................................................... 40
Experiment menu.............................................................................................................................................41
Data menu ....................................................................................................................................................... 43
Analyze menu................................................................................................................................................... 47
View menu........................................................................................................................................................51
Setup menu ......................................................................................................................................................57
Window menu.................................................................................................................................................. 58
Help menu........................................................................................................................................................59
APPENDIX A TROUBLESHOOTING GUIDE................................................................................................ 61
6 Spectro Pro
APPENDIX B USING SPECTRO PRO ON A NETWORK............................................................................. 65
General principles...........................................................................................................................................65
Spectro Pro preferences.................................................................................................................................. 65
Macintosh........................................................................................................................................................65
Windows...........................................................................................................................................................66
Student use of Spectro Pro on a network.........................................................................................................66
APPENDIX C INTERFACES COMPATIBLE WITH SPECTRO PRO........................................................67
Which Interface? .............................................................................................................................................67
APPENDIX D SENSORS FOR USE WITH SPECTRO PRO..........................................................................69
Sensors supported by all interfaces.................................................................................................................69
Additional sensors for the ULI and LabPro....................................................................................................69
Sensor for LabPro only ................................................................................................................................... 69
Experiment and calibration files.....................................................................................................................69
ENSOR PRICE LIST
S
...............................................................................................................................................70
Spectro Pro 7
Spectro Pro Overview
Overview
The Spectro Pro user’s guide is divided into four main sections: This
Overview, a How To section, a Teacher’s Guide, and the Spectro Pro
Reference. This Overview concludes with a “Quick Referen ce” Section
for the eager. In s tru ctors us in g Spectro Pro in the classroom will want to
read the Teach er’s Guide for helpful tips. The How To section explains
common operations with Spectro Pro. You can read it in any order. The
Reference Section explains the function of all the menu items and how
to use them. On-line help is available: Choose Help from the Apple
menu (Macintosh) o r the Help menu (Windows).
Initial software installation and the connection of the interface are
explained in the Teacher’s Guide. Refer to the troubleshooting chart in
Appendix A if you have problems. Detailed information for network us e
can be found in Appendix B. Appendix C reviews the interfaces that can
be used with Spectro Pro, and how to choose among them. A list of
spectrophotometers compatible with Spectro Pro is in Appendix D.
Some familiarity with the use of Macintosh or Windows computers and
application software is assumed in this manual.
Spectro Pro has been designed by Gretchen Stahmer DeMoss, Dan
Holmquist, Jessica Fink, and Diana Gordon of Vernier Software &
Technology, and by Stephen Beardslee and Mary Dygert at the Center
for Science and Mathematics Teaching at Tufts University. The d esign
was implemented by Stephen Beardslee, Mary Dygert and Gretchen
Stahmer DeMoss.
Spectro Pro is copyrighted by Vernier Software & Technology and Tufts
University. You are permitted to make as many copies as you wish of the
Spectro Pro software and the User's for use in your own high school,
middle school, or college department. You may use Spectro Pro on
networks within your school or department at no extra cost. Our site
license also permits your students to load a copy of Spectro Pro on their
home co mputers.
The Spectro Pro manual is copyright ©2001 by Vernier Software &
Technology. John Gastineau wrote this manual, with revisions by Diana
Gordon. Macintosh is a registered trademark of Apple Computer, Inc.
Microsoft, Windows, Windows NT, and Win32s are either registered
trademarks or trademarks of Microsoft, Inc.
Spectro Pro 8
10 Spectr o Pro
Spectro Pro Quick Start
Purpose
Install software
Attach spectrophotometer
This section is provided for those who do not read software manuals. It
outlines the essential steps to get started with Spectro Pro.
To install Spectro
•
Place the Spectro Pro CD in the CD-ROM drive of your computer.
•
Double-click the icon Install Spectro Pro and follow the instructions
on screen.
To install Spectro
95/98/2000/NT 4.0, follow the s e steps
•
Place the Spectro Pro CD in the CD-ROM drive of your computer.
•
If you have Autorun enabled, the installation will launch automatically;
otherwise choose Settings Æ Control Panel from the Start menu.
Double click on Add/Remove Programs. Click on the Install b utton in
the resulting dialog box.
•
The Spectro Pro installer will launch, and a series of dialog boxes will
step you through the installation of the Spectro Pro software. You will
be given the opportunity to either accept the default directory or enter a
different directory.
•
If using a Sp ec 20D or D+ (digital signal):
You may connect directly to a computer Serial Port using an SP CIBM cable for PC or an SPC-MAC cable for Mac. If a serial port is
not available, connect through an interface as directed below (See
“If using a Spec 20 or 20+”), or use a Key Span serial-to-USB
adapter.
Pro
on a Power Macintosh, follow these steps
Pro
on a computer running Windows
:
:
•
If using a 20 Genesys (digital signal only):
You may connect directly to a computer Serial Port using a GEN-PC
cable for PC or a GEN-MAC cable for Mac.
•
If using a Flinn spectrophotomete r (digital signal only):
You may connect directly to a computer Serial Port using an SP CFL I cable for PC or SPC-FLM cable for Mac.
•
If using a Sp ec 20 or 20+ (analog signal only):
You must connect to a computer interface:
¾ LabPro: Connect to CH1 of a Vernier LabPro with an SPC-BTA
cable.
¾ ULI: Connect to DIN1 of a ULI using an SPC-DIN cable.
¾ Serial Box Interface: Connect to Port 1 of a Serial Box Interface
using an SPC-DIN cable.
¾ Attach the power adapter to the interface and to a source of
115VAC.
¾ Connect the interface to the computer using the supplied cable.
On the Macintosh you can use any serial port, including the
modem and printer ports. On the PC you can use any of the
COM1, 2, 3 or 4 serial ports. LabPro users can also use the USB
port and cable on a USB-equipped PC or Macintosh.
Spectro Pro 8
USB Connection
Tur n on spectrophotometer
Start up Spectro
Pro
If you have a USB-only comput er, you may c onsider using one of the
following options:
1. For Macintosh computers, attach a Keyspan USB Twin Serial
Adapter*, Part #USA-28x (for information, see www.keyspan.com).
Use Printer Port port selection.
Note:
2. For PC computers, attach a Keyspan High Speed USB Adapter*,
Part #USA-19W (for information, see www.keyspan.com).
Note
:
Use COM 3 por t selection.
3. If y o u have an analog Spec 20 or Spec 20+ (or a Spec 20D or D+,
which have analog as well as digital capability), yo u can connect to
Channel 1 or a LabPro Interface using the SPC-BTA cable.
Note
:
The LabPro interface itself can connect to the USB port of a
Macintosh or PC computer and use Spectro Pro software.
Fol lowing the manufacturer’s dir ections, turn on y our
spectrophotometer.
Locate the Spectro Pro icon and double-click on it, or use the Start menu
(Windows 95/98/NT/ME). If the most recently used spectrophotometer
or interface is not detected, the Setup Interface Box will appear on your
screen.
Select the port to which your spectrophotometer or interface is
connected, and click on the Scan button. An icon representing your
interface or spectrophotometer will appear in the toolbar. (Note: your
spectrophotometer must be turned on for this to be successful.) When
this has occurred, click on the OK button in the Setup Interface box. You
will see the following screen on your monitor.
∗
∗
The Keyspan Adapters have not been extensively tested with Spect ro Pro, nor have
other brands of USB to S er ial adapters been examined.
12 Spectr o Pro
Select Desired Experimental
Setup
•
From the mode buttons in the toolbar select one of the following
experiment files: Absorbance vs. Time, Absorbance vs.
Concentration, or Absorbance vs. Wavelength.
•
Follow the on-screen instructions.
•
Spectro Pro is now ready to collect data.
Collect data
Adjust graph
Insert linear regression line
If you need more
•
Click on the
Collect
button on the toolbar. Follow calibration
instructions, as required, and begin data collection. Spectro Pro will
plot data in the graph window. When you have completed data
collection, click on the Stop button. (In the Absorbance vs. Time
mode data collection will stop automatically at the end of the
designated time.)
•
You can adjust most features of the graph by double clicking the
graph and making changes in the resulting dialog box.
•
First, select a portion of the graphed data by dragging across
it.
•
Then click on the linear fit button on the toolbar.
If you need more information about using Spectro Pro, check the on-line
help files.
Spectro Pro 8
Change axis limits manually
How To
How To
In the How To section you will learn to perform specific functions in
Spectro Pro. The tasks are organized in six broad categories: graph
appearance, data collection options, non-graph windows, data analysis,
data tables , and saving a nd printing data.
If you have further questions, go to the reference section and read the
descriptions of the relevant menu items, or check the index for other
references.
Change Graph Appearance
There are many ways that you might want to change the appearance of
the initial graph. The range of the x or y axis might not be ideal. Or, you
might want to plot other quantities on each axis. You can change most
elements of the graph directly by clicking on them, so if you are not s u re
how to change a given item, begin by clicking on it and see what
happens. Here are some things you can quickly change on a graph.
Often you will measure some quantity and the plotted line will only fill a
portion of the screen. You can quickly change the range of values plotted
by clicking the numbers at the ends of the graph axes. Type a new value
and press enter.
Change axis limits
automatically
Zoom in on a graph
To make the plotted data fill the graph window for this particular
collection of data, click the Autoscale Once button on the toolbar.
To turn automatic scaling on for all subsequent collections of data
choose V iew Æ Set Axes to Autoscale.
To change just the x- or just the y-axis limits, click on the desired axis.
You will see a dialog
box:
Choose the type of
scaling you want.
Autoscale Once will
set the axis limits so
the data just fill the
axis. The origin may
not necessarily be
included unless you
choose Autoscale
from 0, in which case
the origin is always included. Manual scaling allows you to enter the
minimum and maximum limits manually. The choice made here will
determine how Spectro Pro scales a new graph.
To enlarge a portion of a graph to fill the screen, drag across the
desired area with the mouse, leaving a rectangle on the graph
enclosing the area of interest. Then click on th e Zoom In button
on the toolbar. If you don’t like what you see, you can reverse the
action by clicking the Undo Zoom button.
The Zoom Out button will double the range of both the x and y
axes. It does not undo a Zo om In—Undo Zoom does that.
Spectro Pro 8
How To
Scroll to a new portion of
graph without rescaling
Change what is plotted
Change other graph options
Sometimes the plotted data will extend off the screen. The arrows at the
ends of the vertical and horizontal axes can be u sed to scroll across the
data. Using the scroll arrows is equivalent to changing both extremes of
the axis limits at the same time while maintaining the same interval
between extremes.
The default plot will usually be the sensor output as a function of time or
a prompted input. You may want to plot some other quantities. Click
either on the x- or y-axis label to get a check box list of all the possible
quantities for plotting. Some combinations will not be useful. If you
don’t see what you want to plot, you may b e ab le to create a new column
of data based on the raw data. See create new columns below. Once
you’ve define d a new column you can plot it.
If you double-click on a graph, you will get a dialog box that allows you
to change a number of graph options. Brief descriptions follow; for
additional information see Spectro Pro reference.
The following functions are found on the Graph Options dialog. Double
click a graph to open this dialog box.
Select point protectors as desired. A point protector outlines a data point.
See data points directl y (poi nt
protectors)
You may want to outline every 5th or 10th point to keep the graph from
getting crowded.
Adding a legend opens a floating box holding a key to the plotted data.
Add/remove a legend
Connect data points
Select the Connecting Line option to connect data points with lines.
Without this option selected individual data points are visible.
Select or deselect the grid as desired. You can als o adjust the line style
Add/remove the grid
and color of the gridlines in this dialog box.
Select or deselect the Graph Title option as desired. Spectro Pro
Graph title
attempts to create a title for a graph based on the axis labels, but you can
override the automatic title by entering text in the Graph Title f ield.
16 Spectr o Pro
How To
Data Collection Options
The best way to set up Spectro Pro for a particular experiment is to open
an experiment file. Spectro Pro comes with experiment files that load
appropriate data collection parameters and prepare Spectro Pro to
receive data. Even if you want to use your own custom configuration,
these files are good starting points.
Spectro Pro offers three data collection options:
•
Absorbance vs. Time
•
Absorbance vs. Concentration
•
Absorbance vs. Wavelength
You may select a data collection option in one of three ways:
(1) Click on the appropriate icon in the toolbar;
(2) Choose the appropriate mode from the File menu.
Or (3) choose Open from the File menu. You will see files for the three
possible modes of data collection (Absorbance vs. Time, Absorbance vs.
Concentration, and Absorbance vs. Wavelength). An additional folder
holds sample data files. (You can also save special experiment files you
create in this location.) Select the file of your choice.
Spectro Pro is now ready t o acquire data.
Spectro Pro 8
How To
Set sampling speed
(data collection rate)
In the Absorbance vs. Time mode, Experiment Length and Sampling
Rate can be selected. Click Setup on the toolbar, and select “Setup
Absorbance vs. Time” to access this feature.
In the Data Collection Sampling tab set the time units you want and the
sampling rate, i.e., the number of points collected each second (select
from 2, 1, .5, or .1 samples/second), minute (select from 60, 30, 6, 1, .25
samples/minute), or hour (select from 3600, 1800, 360, 60, 25
samples/hour). Sampling speed is a trade-off; too fast a speed yields
unwieldy data sets, while too slow a collection rate will miss important
experimental details. The maximum sampling speed depends on the
interface used and the number of input channels. Spectro Pro can collect
at most 30,000 points in one input channel.
Set the total time of data collection for Real Time Collect, Repeat and
Set experiment length
Selected Events modes in the Data Collection Sampling tab. You can
also set the experiment length by changing the maximum time axis label
to the desired value.
If the column used for the
Sort data
horizontal axis is not in
ascending or descending order
the graph will not be drawn
correctly when connecting
lines are enabled. This can
easily happen when the column
consists of prompted entries.
Choose Sort Data from the
Data menu, choose the column
by which to sort, click
ascending or descending as
desired, and click OK.
18 Spectr o Pro
How To
View Other Window Types
The Windows menu contains commands that add or replace windows on
the Spectro Pro screen. Since each new window reduces the screen area
available for the existing windows, the precise action of the window
commands depends on the currently active window. New Tall Window
halves the width of the current window and creates a new window of
vertical orientation of the selected type. Similarly, New Window Wide
halves the height of the current window and creates a wide window of
the selected type. Replace Window replaces the selected window with a
window of the newly selected type.
Graph
Table
Text
Meter
Choose New Tall Window Æ Graph from the Window menu. A new
graph window will be created. Note that it may be more useful to create
a new pane in a graph window instead since less screen area is required .
See Graph Layout in the View menu of Spectro Pro Reference for more
information.
Choose New Tall Window Æ Table from the Window menu. A new data
table window will be created.
Choose New Tall Window Æ Text from the Window menu. A new
window will be created for text entry. You can use this window for
laboratory instructions, information about the experiment, or other notes.
Choose New Tall Window Æ Meter from the Window menu. A dialog
box will open which allows you to select the data columns to be
displayed in a digital meter window. Then a new window will be created
containing the selected digital readouts. Double-click on the meter
window to change which quantities are displayed.
Spectro Pro 8
How To
Analyze Data
Read values from cursor
Read delta values between
two points
Read values from graph
Display tangent lines
Compare runs
As you move the mouse cursor around the graph the coordinates of the
point directly under the cursor point appear in the rightmost area of the
status bar at the bottom of the main Spectro Pro window.
You may click, hold, and drag the mouse cursor from one point to
another on the graph to get the delta between two points. The horizontal
and vertical distance (∆x and ∆y) between the two points is displayed
next to the mouse cursor position in the rightmost area of the status bar
at the bottom of the main Spectro Pro window.
Choose Examine from the Analyze menu.
A floating box will appear, accompanied by the numerical value at the
mouse pointer position. As the mouse cursor is moved across the graph,
the readout will change and the data table will scroll to highlight the
associated numerical values.
To draw tangent lines and read the slope of those lines, choose
Tangent from the Analyze menu (or click on the tangent line
button on the toolbar) and move the pointer to the place where you want
the slope. A floating box will appear, containing the numerical value of
the data and the slope of the tangent line at the pointer position. The
number of points used in calculating the tangent may be set by choosing
Options fr om the Experiment menu.
Often you will want to compare two similar r uns of collected data. When
you get the first useful run, choose Store Latest Run from the Data
menu. Now you may take additional data and the stored run will not be
lost. The data will be retained through subseq uent data collections, and
can be displayed or hidden as desired. Stored runs are numbered
sequentially. Any number of runs can be stored, and will be saved wh en
yo u save an experiment to di sk.
The Data menu has four more relevant functions. Hide Run will
temporarily remove the selected run from the graph, Show Run will put
it back, Rename Run allows changing the displayed name of a selected
stored run, and About Run shows the timestamp of the d ata and allows
you to enter notes about the run. Using the Hide/Show functions you can
superimpose any desired set of runs.
Fit a line to data
(linear regression)
Interpolate between points
Fit functions to data
20 Spectr o Pro
To fit a straight line to your data, select the d esired portion of the
data by dragging across it. Next, choose Linear Fit from the
Analyze menu (or click on the linear regression button on the toolbar). A
straight line will be fit to the indicated data, and the slope and in tercept
information will be displayed in a floating box. Displayed precision can
be adjusted by double-clicking on the floating box to open a new dialog
box.
To interpolate between data points on a line, click on the
Interpolate button on the toolbar. To interpolate between data
points on a curve, first fit a function to a range of data. choose
Interpolate from the Analyze menu. The floating box for the curve fit
will expand to show the coordinates of points along the fitted curve.
Move the mouse pointer to the place you want to interpolate.
To fit more complex functions to your data choose Automatic
How To
Curve Fit from the Analyze menu (or click on the Automatic Curve Fit
button on the toolbar). You will see the following dialog box. To fit to
just a part of your data, you must first select the desired portion of the
data by dragging across it.
Manual Fit
(Model Data)
Now choose a mathematical relation from the list at the lower left. You
may need to scroll through the list to find the appropriate function. The
polynomial choice also requires that you set the degree of the
polynomial. Next, choose the data set you want to use from the Perform
Fit On menu. Click on Try Fit to see the result. If you like, choose
another function or data column for another trial fit. You can also select
a different ran ge of data by dragging acros s the graph regi on. Click on
Try Fit to see the new fit. Once you have a fit that you like, click on OK
to display the fitted curve on your graph. Click on Cancel to discard all
fits. The Save button will place the fitted curve on the main graph
window without closing the dialog box.
If you want a linear regression line to be forced through the origin, select
Automatic Curve Fit, from the Analyze menu and then select
Proportional. The Proportional fit (y=Ax) has a y-intercept value equal
to 0; therefore, this regression line will always pass through the origin of
the graph.
To superimpose a function over your data, make a graph active by
clicking on it once. Select Manual Curve Fit from the Analyze menu. In
the dialog box select a function. Adjust parameters as needed to fit the
function t o your data.
Note that poorly chosen parameters may make the function miss the
graphed region entirely. In this case it is difficult to adjust the parameters
by trial and error. You may want to select parameters carefully so that the
function matches the data at the y-intercept, and adjust values from
there.
Change Displayed Precision
of Fit Parameters
You can adjust eith er the number of significant digits or the number of
decimal places used in displaying fit statistics and parameters. After you
have completed a fit, double-click on the floating box containing the fit
Spectro Pro 8
How To
information. A floating box options dialog will open, allowing you to set
the line color, line style, fit co efficients displayed, and their precision.
22 Spectr o Pro
Perform Data Table Functions
How To
Change what runs appear in
the data table
You can control what is displayed in the Data Table Window. Double
click on the data table to change table options and click on the Table
Layout tab. You will see this tabbed dialog box.
Choose the table layout you need. The choices allow you to display all
columns from all runs, just a single run, or just one column from all
runs. You can further control what is shown in the data table by hiding
individual columns in the Column Options dialog found in the Data
menu, or by do uble-clicking a column header.
The Font Options tab shows a dialog in which you can choose display
font and size for the da t a table.
Spectro Pro 8
How To
Change a column’s name,
color, width, or digits
displayed
Double clicking a column heading or the Run heading will open the
Column Options dialog, allowing you to change the column name,
width, color, or digits displayed. Double clicking the Run header will
allow you to choose a column from a list; double clicking a column
header directly will take you to the Column Options dialog for that
column.
Calculate new values from
raw data (new columns)
Calculated data columns—an
example
If you click in the box for Propagate Changes, all runs for that column
will be affected. Hide Columns will conceal the column in the data table.
You can choose to apply the new point protector to all columns of that
run, all runs for that column, or that column and run only.
You can define rules for columns calculated from spectrophotometer
readings much like you enter formulas in a spreadsheet. The definition
can be entered either be fore or after the data are collected . These new
columns can be graphed just like any other column, even as data are
being collected. The calculated columns can be used for a variety of
purposes, including graphing calculated data or data entered from the
keyboard. These are described in turn below.
As an example, let us create a calculated column, ln Absorbance, and
then plot a graph of ln Absorbance vs. Time:
First, choose New Column/Formula from the Data menu. You will see
the following dialog box, without the entries you are about to make.
Click on the Options tab to be sure this pane is on top.
24 Spectr o Pro
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