PASCO© Interface and Computer Primer

INTRODUCTION:

The PHYS207/208 laboratories now utilize a Web-browser based display format in combination, when necessary, computer controlled data acquisition interface (typically the PASCO CI-700 or 750). Various sensors are plugged into either digital I/O (phone jack style inputs 1 to 4) or analog I/O ports (DIN-9 style inputs A, B and C). To aid in the data acquisition and analysis PASCO module also requires use of a special purpose software package which can be easily reconfigured for the particular need of a experiment. In general all experiment starting configuration will be preset and launched through a Web-browser button at the appropriate place in the lab.

THE MOUSE

CLICKING: Most of the operations of your computer are controlled by locating the cursor on the appropriate symbol (icon) and by clicking (CLICK) or double clicking (DCLICK) the left button of the mouse.

If the operation you have to perform requires clicking the right button this will be shown by CLICK-R or DCLICK-R. Double clicking means pressing the mouse button twice in rapid sequence without moving the mouse. The image of an hour glass appears momentarily indicating that the computer is loading the program, that is, getting ready to do what you requested. It will not do this if you moved the mouse while double clicking.

WINDOWS

The monitor usually displays various ``windows'' with a title bar. If you CLICK anywhere inside the window, the title bar turns blue, and the window is ``active'' (i.e. the computer will respond to any clicks on the ``icons'' on the border of the window).

BASIC OPTIONS:

I.

CLICK on the head bar to ``drag'' the window to a different position.

II.

Enlarge the window by placing the cursor on the corner, a diagonal arrow will appear, then CLICK and drag to change the size of the window.

Depending on which experiment you are performing you will see various windows. These will be discusses separately.

ICONS

The icons that appear at the top right of all windows are (see Fig. 1):

1. EXIT: The window is removed permanently.

2. RESIZE: The size is changed from large to small, or vice-versa.

3. ICONIZE: The window disappears. Its title and icons 1, 2 and 3 appear at the bottom of the screen.

   THE GRAPH WINDOW ICONS: At the bottom left corner of the graph window you will find six icons:

   Figure 1: The Graph Window

   

4. STATISTICS shows/hides statistics for all existing graphs. You must first select the area of the graph you want to analyze by dragging the cursor (CLICK and hold) diagonally across the graph to generate a rectangle that encloses the area chosen. A new box will appear that allows you to select the type of fitting that is suitable to the data. The meaning of ``fitting'' is discussed separately below.

5. CURSOR: Displays cross hairs which can be moved about using the mouse. Simultaneously the coordinates of the cursor position are displayed and this enables the coordinates of graph features to be measured.

6. MAGNIFY: Enlarges any part of a graph. To select the area of the graph you want to enlarge by first CLICKing this icon and then CLICK a point on the graph using a drag motion (click and hold) diagonally across the graph. This will generate a rectangle that selects the area chosen.

7. AUTOSCALE: Scales the $y$-axis and the $x$-axis so that all the data is shown

8. GRAPH SETUP: This icon allows for adding your name to the title of the window, select plot (e.g. connected points, select grid).

9. ADD PLOT: Add another graph; presents a menu of available channels.

At the top left corner of the graph window you find two more icons:

10.

PLOT DATA: Displays various data options.

11.

DATA MENU: Displays the list of all the data sets recorded. CLICK on the one you want to display; a check mark will appear and the corresponding graph will be displayed. CLICK on the one you do not want to display, the check mark will disappear.

THE SCALE OF EACH AXIS:

In order to change the scale of an axis CLICK on any number on that axis; a menu will appear allowing you to enter the minimum and maximum values of the scale, CLICK at the end of the number you want to change, backspace, type the new number, CLICK ``OK'' in the appropriate box.
An alternative way of changing the scale of a graph is to CLICK on the $\oplus$ or $\ominus$ at the bottom right corner of the graph window.

THE SETUP WINDOW ICONS:

Usually you will find the setup window in its ``minimized'' form as shown below:

Figure 2: The Setup Window minimized.

10.

RECORD: DCLICK and the computer begins taking data. The data is stored, and can be recalled.

11.

MONITOR: DCLICK on this and the computer begins taking data. The data is not stored, and it disappears at the end of the run. This allows you to view what the data will look like when you RECORD.

12.

STOP: Stops the run, the data is stored. The run cannot be restarted.

13.

PAUSE: Stops taking data till you CLICK again and the run is restarted.

14.

DATA BOX: This area contains the color coded list of all the runs. Delete a run by clicking on it, and using the back arrow at the top right corner of the keyboard.

15.

SAMPLING: Allows for terminating a data run after a predeterminate time.

16.

SIGNAL GENERATOR: Starts a built-in signal generator (e.g. sine or square waves) and allows control of both frequency and amplitude.

THE TABLE WINDOW ICONS:

Figure 3: The Table Window

17.

STATISTICS: Calculates displays the minimum and maximum value of the data, displays also the mean, and the standard deviation.
NOTE: Subsets of the full data set can be analyzed by using the mouse and highlighting (through a CLICK and drag motion) the rows of interest.

18.

TIME INDEX: Alter the display to include time at which data was recorded.

19.

DIGITS SETUP: Resets the number of significant digits displayed.

20.

DATA MENU: Allows access to data of preceding runs.

THE STATISTICS WINDOW ICONS:

21.

STATISTICS: the fitting menu is displayed; a mathematical expression that approximates the data or other option (e.g. histogram data, calculate the derivate of the curve) may be chosen.

``Fitting'' or regression is the procedure used to find a mathematical expression that matches the function form of the data being analyzed (linear, exponential, etc.).

Figure 4: The Statistics Window and Menu