Difference between revisions of "Introduction to LabVIEW"

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<h1>EG1004 Lab 4: Introduction to LabVIEW</h1>
<h1>EG1004 Lab 4: Introduction to LabVIEW</h1>


== <h2>4.1 OBJECTIVES</h2> ==
== <h2>1 OBJECTIVES</h2> ==


<p>The experimental objective of this lab is to design three systems using LabVIEW:</p>
<p>The experimental objective of this lab is to design three systems using LabVIEW:</p>
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learn the logic of graphical programming during the course of this lab.</p>
learn the logic of graphical programming during the course of this lab.</p>


== <h2>4.2 OVERVIEW</h2> ==
== <h2>2 OVERVIEW</h2> ==
<p><i>Adapted from Introduction to LabVIEW, Six-Hour Course.10</i></p>
<p><i>Adapted from Introduction to LabVIEW, Six-Hour Course.10</i></p>


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<li>CTRL+Z: Undo last action.</li>
<li>CTRL+Z: Undo last action.</li>
</ol>
</ol>
== <h2>4.3 YOUR ASSIGNMENT</h2> ==
== <h2>3 YOUR ASSIGNMENT</h2> ==


<h3>Team PowerPoint Presentation and Individual Lab Report</h3>
<h3>Team PowerPoint Presentation and Individual Lab Report</h3>
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</ul>
</ul>


== <h2>4.4 MATERIALS AND EQUIPMENT</h2> ==
== <h2>4 MATERIALS AND EQUIPMENT</h2> ==


<ul>
<ul>
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</ul>
</ul>


== <h2>4.5 PROCEDURE</h2> ==
== <h2>5 PROCEDURE</h2> ==


<ol>
<ol>
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<li>On the left window, pull down the <b><i>Window</i></b>
<li>On the left window, pull down the <b><i>Window</i></b>
menu again, select <b><i>Show Controls Palette</i></b>. At this point your screen should look
menu again, select <b><i>Show Controls Palette</i></b>. At this point your screen should look
like Figure 4.3. Note the <b><i>Controls Palette</i></b> and the <b><i>Tools
like Figure 3. Note the <b><i>Controls Palette</i></b> and the <b><i>Tools
Palette</i></b>, and their icons.</li>
Palette</i></b>, and their icons.</li>
</ol>
</ol>


<p align=center>[[Image:lab4_1.gif]]</p>
<p align=center>[[Image:lab_labview_1.gif]]</p>


<p class=caption>Figure 4.3: LabVIEW workspace</p>
<p class=caption>Figure 3: LabVIEW workspace</p>


<p><b>Remember: </b><i>You are required to take notes. Experimental details are
<p><b>Remember: </b><i>You are required to take notes. Experimental details are
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<ol>
<ol>
<li>Select the <b>Num Ctrls</b> icon [[Image:lab4_2.gif]] on the <b>Controls Palette</b> (see Figure 4.4). This
<li>Select the <b>Num Ctrls</b> icon [[Image:lab_labview_2.gif]] on the <b>Controls Palette</b> (see Figure 4). This
will bring up the window shown in Figure 4.5
will bring up the window shown in Figure 5


<p align=center>[[Image:lab4_3.gif]]</p>
<p align=center>[[Image:lab_labview_3.gif]]</p>


<p class=caption>Figure 4.4: Controls Palette</p>
<p class=caption>Figure 4: Controls Palette</p>


<p align=center>[[Image:lab4_5.gif]]</p>
<p align=center>[[Image:lab_labview_5.gif]]</p>


<p class=caption>Figure 4.5: Numerical Controls window</p>
<p class=caption>Figure 5: Numerical Controls window</p>


<li>Then select Horizontal Pointer Slide from the icons shown. Click on the left window to place the slide
<li>Then select Horizontal Pointer Slide from the icons shown. Click on the left window to place the slide
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<li>Click on the number <i>10
<li>Click on the number <i>10


</i>and change it to <i>2</i>. Now the slide control will look like Figure 4.6.</li>
</i>and change it to <i>2</i>. Now the slide control will look like Figure 6.</li>


<p align=center>[[Image:lab4_6.gif]]</p>
<p align=center>[[Image:lab_labview_6.gif]]</p>


<p class=caption>Figure 4.6: Slide control with range changed from 10 to 2</p>
<p class=caption>Figure 6: Slide control with range changed from 10 to 2</p>


<li>Right click on the slide to bring up a pull down menu. Select <b>Representation</b>,
<li>Right click on the slide to bring up a pull down menu. Select <b>Representation</b>,
and choose the <b>I32 </b>icon. Figure 4.7
and choose the <b>I32 </b>icon. Figure 7
shows what the pull down menus look like, and the I32 icon. This completes the
shows what the pull down menus look like, and the I32 icon. This completes the
slide control on the front panel.</li>
slide control on the front panel.</li>


<p align=center>[[Image:lab4_7.gif]]</p>
<p align=center>[[Image:lab_labview_7.gif]]</p>


<p class=caption>Figure 4.7: I32 Representation pull down menus</p>
<p class=caption>Figure 7: I32 Representation pull down menus</p>
</ol>
</ol>


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<ol>
<ol>
<li>On the Controls palette, select the <b>LEDs</b> icon [[Image:lab4_8.gif]].
<li>On the Controls palette, select the <b>LEDs</b> icon [[Image:lab_labview_8.gif]].
This will bring up the window shown in Figure 4.8.</li>
This will bring up the window shown in Figure 8.</li>


<p align=center>[[Image:lab4_9.gif]]</p>
<p align=center>[[Image:lab_labview_9.gif]]</p>


<p class=caption>Figure 4.8: LEDs Window</p>
<p class=caption>Figure 8: LEDs Window</p>


<li>Select the <b>Round LED</b> icon from the icons shown.
<li>Select the <b>Round LED</b> icon from the icons shown.
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<li>Rename the three LEDs to correspond to the functions the calculator will be
<li>Rename the three LEDs to correspond to the functions the calculator will be
performing: add, subtract, and multiply. To rename each LED, click on the
performing: add, subtract, and multiply. To rename each LED, click on the
<b>Edit Text</b> icon [[Image:lab4_10.gif]] on the <b>Tools
<b>Edit Text</b> icon [[Image:lab_labview_10.gif]] on the <b>Tools
palette</b>. Then click on the ‘Boolean’ label on each LED and replace it with
palette</b>. Then click on the ‘Boolean’ label on each LED and replace it with
the proper text: “add�? for the left light, “subtract�? for the center light, and
the proper text: “add�? for the left light, “subtract�? for the center light, and
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<ol>
<ol>
<li>On the <b>Controls palette</b>, click on the <b>Num Ctrls</b> icon. This will bring up the
<li>On the <b>Controls palette</b>, click on the <b>Num Ctrls</b> icon. This will bring up the
window shown in Figure 4.5 again.</li>
window shown in Figure 5 again.</li>


<li>Click on the <b>Num Ctrl</b> icon and click on the left window to the left of
<li>Click on the <b>Num Ctrl</b> icon and click on the left window to the left of
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<ol>
<ol>
<li>On the Controls palette, click on the <b>Num Inds</b> icon [[Image:lab4_11.gif]].
<li>On the Controls palette, click on the <b>Num Inds</b> icon [[Image:lab_labview_11.gif]].
This will bring up the window shown in Figure 4.9.</li>
This will bring up the window shown in Figure 9.</li>


<p align=center>[[Image:lab4_12.gif]]</p>
<p align=center>[[Image:lab_labview_12.gif]]</p>


<p class=caption>Figure 4.9: Num Inds Window</p>
<p class=caption>Figure 9: Num Inds Window</p>


<li>Click on the <b>Num Ind</b> icon and click on the left window
<li>Click on the <b>Num Ind</b> icon and click on the left window
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<li>You are now finished constructing the front panel. The finished <b>Front
<li>You are now finished constructing the front panel. The finished <b>Front
Panel</b> should look like Figure 4.10:</li>
Panel</b> should look like Figure 10:</li>
</ol>
</ol>


</ol>
</ol>


<p align=center>[[Image:lab4_13.gif]]</p>
<p align=center>[[Image:lab_labview_13.gif]]</p>


<p class=caption>Figure 4.10: Finished Front Panel</p>
<p class=caption>Figure 10: Finished Front Panel</p>


<p>As we stated earlier, on the back panel there are icons corresponding to everything you put
<p>As we stated earlier, on the back panel there are icons corresponding to everything you put
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indicator to the bottom of the window. Place the slide node on the left edge of the window.
indicator to the bottom of the window. Place the slide node on the left edge of the window.
This will leave a large area in the middle that you will fill in at the next few
This will leave a large area in the middle that you will fill in at the next few
steps. Your back panel should now look like Figure 4.11.</li>
steps. Your back panel should now look like Figure 11.</li>


<p align=center>[[Image:lab4_14.gif]]</p>
<p align=center>[[Image:lab_labview_14.gif]]</p>


<p clas=caption>Figure 4.11: Rearranged Back Panel</p>
<p clas=caption>Figure 11: Rearranged Back Panel</p>


<li>In the block diagram (back panel) of LabVIEW, go to the menu bar, select window,
<li>In the block diagram (back panel) of LabVIEW, go to the menu bar, select window,
and choose “Show Functions Palette�?, just as shown on Figure 4.12a. This will bring up the
and choose “Show Functions Palette�?, just as shown on Figure 12a. This will bring up the
Functions Palette, shown in Figure 4.12b.</li>
Functions Palette, shown in Figure 12b.</li>


<p align=center>[[Image:lab4_15.gif]]</p>
<p align=center>[[Image:lab_labview_15.gif]]</p>


<p class=caption>Figure 4.12a: How to bring up the Functions Palette</p>
<p class=caption>Figure 12a: How to bring up the Functions Palette</p>


<p align=center>[[Image:lab4_16.gif]]</p>
<p align=center>[[Image:lab_labview_16.gif]]</p>


<p class=caption>Figure 4.12b: Functions Palette</p>
<p class=caption>Figure 12b: Functions Palette</p>


<li>Clink on the <b>Exec Ctrl</b> icon [[Image:lab4_17.gif]]. This will
<li>Clink on the <b>Exec Ctrl</b> icon [[Image:lab_labview_17.gif]]. This will
bring up the <b><i>Exec Ctrl</i></b> window, shown in Figure 4.13.</li>
bring up the <b><i>Exec Ctrl</i></b> window, shown in Figure 13.</li>


<p align=center>[[Image:lab4_18.gif]]</p>
<p align=center>[[Image:lab_labview_18.gif]]</p>


<p class=caption>Figure 4.13: Exec Ctrl Window</p>
<p class=caption>Figure 13: Exec Ctrl Window</p>


<li>Click on the <b>Case Structure</b> icon. Click on the right window to locate it on the
<li>Click on the <b>Case Structure</b> icon. Click on the right window to locate it on the
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<li>We will now start
<li>We will now start
connecting things. First, we need to access the proper tool. On the Tools
connecting things. First, we need to access the proper tool. On the Tools
Palette, chose the “Connect Wire�? icon [[Image:lab4_19.gif]]. We’ll now connect
Palette, chose the “Connect Wire�? icon [[Image:lab_labview_19.gif]]. We’ll now connect
the slide to the case structure. Connect the slide to the <b>case structure</b> by clicking on the slide object, and then on the
the slide to the case structure. Connect the slide to the <b>case structure</b> by clicking on the slide object, and then on the
question mark on the left side of the case structure. Your back panel should
question mark on the left side of the case structure. Your back panel should
now look like Figure 4.14.</li>
now look like Figure 14.</li>


<p align=center>[[Image:lab4_20.jpg]]</p>
<p align=center>[[Image:lab_labview_20.jpg]]</p>


<p class=caption>Figure 4.14: Back Panel Slide to Case Structure Connection</p>
<p class=caption>Figure 14: Back Panel Slide to Case Structure Connection</p>


<li>When the case
<li>When the case
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right-click anywhere on the <b>case
right-click anywhere on the <b>case
structure</b> and select <b>Add Case After</b>,
structure</b> and select <b>Add Case After</b>,
as shown in Figure 4.15.</li>
as shown in Figure 15.</li>


<p align=center>[[Image:lab4_21.gif]]</p>
<p align=center>[[Image:lab_labview_21.gif]]</p>


<p class=caption>Figure 4.15: Adding Another Case</p>
<p class=caption>Figure 15: Adding Another Case</p>


<li>Now we’ll add the mathematical operations that the calculator should perform for
<li>Now we’ll add the mathematical operations that the calculator should perform for
each case. On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>
each case. On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>
icon <b>[[Image:lab4_33.gif]]</b> from the main <b><i>Functions
icon <b>[[Image:lab_labview_33.gif]]</b> from the main <b><i>Functions
Palette</i></b>. This will bring up the Arith/Compare window shown in Figure
Palette</i></b>. This will bring up the Arith/Compare window shown in Figure 17.</li>
4.17.</li>


<p align=center>[[Image:lab4_23.gif]]</p>
<p align=center>[[Image:lab_labview_23.gif]]</p>


<p class=caption>Figure 4.17: Arith/Compare Window</p>
<p class=caption>Figure 17: Arith/Compare Window</p>


<li>On the Arith/Compare window, click on the <b>Numeric</b> icon
<li>On the Arith/Compare window, click on the <b>Numeric</b> icon
[[Image:lab4_24.gif]]. This will bring up the Express Numeric window
[[Image:lab_labview_24.gif]]. This will bring up the Express Numeric window
shown in Figure 4.18.</li>
shown in Figure 18.</li>


<p align=center>[[Image:lab4_25.gif]]</p>
<p align=center>[[Image:lab_labview_25.gif]]</p>


<p class=caption>Figure 4.18: Express Numeric Window</p>
<p class=caption>Figure 18: Express Numeric Window</p>


<li>Click on the left arrow at the top of the case structure box. This should change the
<li>Click on the left arrow at the top of the case structure box. This should change the
caption for the case structure to <b><i>0</i></b>. In the <b><i>Express Numeric</i></b>
caption for the case structure to <b><i>0</i></b>. In the <b><i>Express Numeric</i></b>


Window, click on the Add icon <b>[[Image:lab4_26.gif]]</b>, and click on a
Window, click on the Add icon <b>[[Image:lab_labview_26.gif]]</b>, and click on a
location in the middle of the case structure box to place it.</li>
location in the middle of the case structure box to place it.</li>


<li>Click on the right arrow at the top of the case structure box. This should change the
<li>Click on the right arrow at the top of the case structure box. This should change the
caption for the case structure to <b><i>1</i></b>. In the <b><i>Express Numeric</i></b>
caption for the case structure to <b><i>1</i></b>. In the <b><i>Express Numeric</i></b>
Window, click on the Subtract icon <b>[[Image:lab4_27.gif]]</b>, and click on
Window, click on the Subtract icon <b>[[Image:lab_labview_27.gif]]</b>, and click on
a location in the middle of the case structure to place it.</li>
a location in the middle of the case structure to place it.</li>


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changing the number in the caption to <b><i>2</i></b>. In the <b><i>Express Numeric</i></b>
changing the number in the caption to <b><i>2</i></b>. In the <b><i>Express Numeric</i></b>


Window, click on the Multiply icon <b>[[Image:lab4_28.gif]]</b>, and click on
Window, click on the Multiply icon <b>[[Image:lab_labview_28.gif]]</b>, and click on
a location in the middle of the case structure to place it. At this point, each case should
a location in the middle of the case structure to place it. At this point, each case should
look like the ones shown in Figure 4.19. You can check each case by clicking on the left and
look like the ones shown in Figure 19. You can check each case by clicking on the left and
right arrows to change the case number in the caption.</li>
right arrows to change the case number in the caption.</li>


<p align=center>[[Image:lab4_29.gif]][[Image:lab4_30.jpg]][[Image:lab4_31.gif]]</p>
<p align=center>[[Image:lab_labview_29.gif]][[Image:lab_labview_30.jpg]][[Image:lab_labview_31.gif]]</p>


<p class=caption>Figure 4.19: Case Structure Cases</p>
<p class=caption>Figure 19: Case Structure Cases</p>


<li>We now need to wire
<li>We now need to wire
Line 409: Line 408:
clicking on the left arrow until the caption reads <b><i>0</i></b>. The triangle inside
clicking on the left arrow until the caption reads <b><i>0</i></b>. The triangle inside
should be addition, with a plus sign in the middle. Once again, click on the
should be addition, with a plus sign in the middle. Once again, click on the
“Connect Wire�? icon [[Image:lab4_19.gif]] on the Tools
“Connect Wire�? icon [[Image:lab_labview_19.gif]] on the Tools
Palette. Click on the leftmost Numeric icon, and click on the top left side of
Palette. Click on the leftmost Numeric icon, and click on the top left side of
the operation triangle to wire the first numeric input to the input of the
the operation triangle to wire the first numeric input to the input of the
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will display the output of the addition calculation in the “Numeric 3�? box on
will display the output of the addition calculation in the “Numeric 3�? box on
the front panel. At this point you’ve completed having the calculator do
the front panel. At this point you’ve completed having the calculator do
addition. Your back panel should look like Figure 4.20.</li>
addition. Your back panel should look like Figure 20.</li>


<p align=center>[[Image:lab4_32.gif]]</p>
<p align=center>[[Image:lab_labview_32.gif]]</p>


<p class=caption>Figure 4.20: Completed Back Panel for Addition</p>
<p class=caption>Figure 20: Completed Back Panel for Addition</p>


<li>We now have to do the
<li>We now have to do the
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caption says “0, Default�?. First, we’re going to repeat Steps 7 and 8 to bring
caption says “0, Default�?. First, we’re going to repeat Steps 7 and 8 to bring
up the <b><i>Express Numeric</i></b> window: On the <b><i>Functions Palette</i></b>, click
up the <b><i>Express Numeric</i></b> window: On the <b><i>Functions Palette</i></b>, click
on the <b>Arith/Compare</b> icon [[Image:lab4_33.gif]] from the main <b>Functions
on the <b>Arith/Compare</b> icon [[Image:lab_labview_33.gif]] from the main <b>Functions
Palette</b>. On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab4_24.gif]]. This will bring up the Express Numeric window shown in
Palette</b>. On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab_labview_24.gif]].
Figure 4.18. On the Express Numeric window, click the upward facing arrow. This
This will bring up the Express Numeric window shown in
will bring up the Arithmetic and Comparison window shown in Figure 4.21.</li>
Figure 18. On the Express Numeric window, click the upward facing arrow. This
will bring up the Arithmetic and Comparison window shown in Figure 21.</li>


<p align=center>[[Image:lab4_23.gif]]</p>
<p align=center>[[Image:lab_labview_23.gif]]</p>


<p class=caption>Figure 4.21: Arithmetic and Comparison Window</p>
<p class=caption>Figure 21: Arithmetic and Comparison Window</p>


<li>On the <b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon
<li>On the <b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon
[[Image:lab4_36.gif]], which will bring up the Express Boolean
[[Image:lab_labview_36.gif]], which will bring up the Express Boolean
window shown in Figure 4.22.</li>
window shown in Figure 22.</li>


<p align=center>[[Image:lab4_37.gif]]</p>
<p align=center>[[Image:lab_labview_37.gif]]</p>


<p class=caption>Figure 4.22: Express Boolean Window</p>
<p class=caption>Figure 22: Express Boolean Window</p>


<li>We are now going to
<li>We are now going to
put three Boolean constants into the case structure. Since this is case 0,
put three Boolean constants into the case structure. Since this is case 0,
which corresponds to add, we want to have the add indicator to be true, and the
which corresponds to add, we want to have the add indicator to be true, and the
other two to be false. We do this by clicking on the True Constant icon [[Image:lab4_42.gif]], and then clicking inside the case structure on the right
other two to be false. We do this by clicking on the True Constant icon [[Image:lab_labview_42.gif]], and then clicking inside the case structure on the right
side to the left of the add indicator that’s outside the case structure. We
side to the left of the add indicator that’s outside the case structure. We
then select the False Constant icon [[Image:lab4_43.gif]] and place it inside the case structure on the right side next to the Subtract and Multiply indicators.</li>
then select the False Constant icon [[Image:lab_labview_43.gif]] and place it inside the case structure on the right side next to the Subtract and Multiply indicators.</li>


<li>We now need to wire
<li>We now need to wire
the constants to their respective indicators. Once again, click on the Connect
the constants to their respective indicators. Once again, click on the Connect
Wire icon [[Image:lab4_19.gif]] on the
Wire icon [[Image:lab_labview_19.gif]] on the
Tools Palette. Click on the right side of the top constant inside the case
Tools Palette. Click on the right side of the top constant inside the case
structure and connect it to the top indicator by clicking on the indicator
structure and connect it to the top indicator by clicking on the indicator
Line 479: Line 479:
Palette</i></b>, click on the <b>Arith/Compare</b>
Palette</i></b>, click on the <b>Arith/Compare</b>


icon [[Image:lab4_33.gif]] from the main <b>Functions
icon [[Image:lab_labview_33.gif]] from the main <b>Functions
Palette</b>. On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab4_24.gif]].
Palette</b>. On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab_labview_24.gif]].
This will bring up the Express Numeric window shown in
This will bring up the Express Numeric window shown in
Figure 4.18. On the Express Numeric window, click the upward facing arrow. This
Figure 18. On the Express Numeric window, click the upward facing arrow. This
will bring up the Arithmetic and Comparison window shown in Figure 4.21. On the
will bring up the Arithmetic and Comparison window shown in Figure 21. On the
<b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon
<b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon
[[Image:lab4_36.gif]], which will bring up the Express Boolean window shown in
[[Image:lab_labview_36.gif]], which will bring up the Express Boolean window shown in
Figure 4.22.Click on the True Constant icon [[Image:lab4_42.gif]] and click inside the right side of the case
Figure 22.Click on the True Constant icon [[Image:lab_labview_42.gif]] and click inside the right side of the case
structure to the left of the Subtract LED. Click on the False Constant icon [[Image:lab4_43.gif]] and click inside the right side of the case
structure to the left of the Subtract LED. Click on the False Constant icon [[Image:lab_labview_43.gif]] and click inside the right side of the case
structure to the left of the Add LED, and again to the left of the Multiply
structure to the left of the Add LED, and again to the left of the Multiply
LED. Click on the Connect Wire icon [[Image:lab4_19.gif]] on the Tools Palette.
LED. Click on the Connect Wire icon [[Image:lab_labview_19.gif]] on the Tools Palette.
Click on the right side of the top constant inside the case structure and
Click on the right side of the top constant inside the case structure and
connect it to the top indicator by clicking on the indicator next. Then do the
connect it to the top indicator by clicking on the indicator next. Then do the
Line 498: Line 498:
icon. The caption should now show <b><i>2</i></b>. We need to have the Subtract
icon. The caption should now show <b><i>2</i></b>. We need to have the Subtract
indicator illuminate for this case. Once again, on the <b><i>Functions Palette</i></b>, click
indicator illuminate for this case. Once again, on the <b><i>Functions Palette</i></b>, click
on the <b>Arith/Compare</b> icon [[Image:lab4_33.gif]]. On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab4_24.gif]]. This will bring up the Express Numeric window shown in
on the <b>Arith/Compare</b> icon [[Image:lab_labview_33.gif]]. On the Arith/Compare window,
Figure 4.18. On the Express Numeric window, click the upward facing arrow. This
click on the <b>Numeric</b> icon [[Image:lab_labview_24.gif]]. This will bring up the Express Numeric window shown in
will bring up the Arithmetic and Comparison window shown in Figure 4.21. On the
Figure 18. On the Express Numeric window, click the upward facing arrow. This
will bring up the Arithmetic and Comparison window shown in Figure 21. On the
<b><i>Arithmetic
<b><i>Arithmetic
and Comparison</i></b> window, click on the Boolean icon [[Image:lab4_36.gif]] which will bring up the Express Boolean window shown in
and Comparison</i></b> window, click on the Boolean icon [[Image:lab_labview_36.gif]] which will bring up the Express Boolean window shown in
Figure 4.22.Click on the True Constant icon [[Image:lab4_42.gif]] and click inside the right side of the case structure
Figure 22. Click on the True Constant icon [[Image:lab_labview_42.gif]] and click inside the right side of the case structure
to the left of the Subtract LED. Click on the False Constant icon [[Image:lab4_43.gif]] and click inside the right side of the case
to the left of the Subtract LED. Click on the False Constant icon [[Image:lab_labview_43.gif]] and click inside the right side of the case
structure to the left of the Add LED, and again to the left of the Multiply
structure to the left of the Add LED, and again to the left of the Multiply
LED. Click on the Connect Wire icon [[Image:lab4_19.gif]] on the
LED. Click on the Connect Wire icon [[Image:lab_labview_19.gif]] on the
Tools Palette. Click on the right side of the top constant inside the case
Tools Palette. Click on the right side of the top constant inside the case
structure and connect it to the top indicator by clicking on the indicator
structure and connect it to the top indicator by clicking on the indicator
Line 514: Line 515:
<li>Before moving on, make sure that the boxes on the edges of the <b>case
<li>Before moving on, make sure that the boxes on the edges of the <b>case
structure</b> are filled in. If they are not, that box has to be wired in
structure</b> are filled in. If they are not, that box has to be wired in
<i>all cases</i> defined by the user.  Your back panel should look like Figure 4.23.</li>
<i>all cases</i> defined by the user.  Your back panel should look like Figure 23.</li>


<p align=center>[[Image:lab4_48.gif]] [[Image:lab4_49.jpg]]</p>
<p align=center>[[Image:lab_labview_48.gif]] [[Image:lab_labview_49.jpg]]</p>


<p class=caption>Figure 4.23: Completed Calculator Back Panel</p>
<p class=caption>Figure 23: Completed Calculator Back Panel</p>
</ol>
</ol>
</ol>
</ol>
Line 531: Line 532:
</ol>
</ol>


<p align=center>[[Image:lab4_50.gif]]</p>
<p align=center>[[Image:lab_labview_50.gif]]</p>


<p class=caption>Figure 4.24: Completed and Working VI</p>
<p class=caption>Figure 24: Completed and Working VI</p>


<li>Once testing is completed:</li>
<li>Once testing is completed:</li>
Line 623: Line 624:
Palette</i></b>, under <b><i>All Functions -&gt; NI Measurements -&gt;Data Acquisition -&gt;
Palette</i></b>, under <b><i>All Functions -&gt; NI Measurements -&gt;Data Acquisition -&gt;


Digital I/O -&gt; Advanced Digital I/O</i></b>. (see Figures 4.25a-f)</li>
Digital I/O -&gt; Advanced Digital I/O</i></b>. (see Figures 25a-f)</li>


<p align=center>[[Image:lab4_51.gif]]</p>
<p align=center>[[Image:lab_labview_51.gif]]</p>


<p class=caption>Figure 4.25a: Functions Palette</p>
<p class=caption>Figure 25a: Functions Palette</p>


<p align=center>[[Image:lab4_52.gif]]</p>
<p align=center>[[Image:lab_labview_52.gif]]</p>


<p class=caption>Figure 4.25b: <i>All Functions</i> palette with <i>NI Measurements</i> pointed out</p>
<p class=caption>Figure 25b: <i>All Functions</i> palette with <i>NI Measurements</i> pointed out</p>


<p align=center>[[Image:lab4_53.jpg]]</p>
<p align=center>[[Image:lab_labview_53.jpg]]</p>


<p class=caption>Figure 4.25c: <i>NI Measurements</i> palette with <i>Data Acquisition</i> pointed out</p>
<p class=caption>Figure 25c: <i>NI Measurements</i> palette with <i>Data Acquisition</i> pointed out</p>


<p align=center>[[Image:lab4_54.gif]]</p>
<p align=center>[[Image:lab_labview_54.gif]]</p>


<p class=caption>Figure 4.25d: <i>Data Acquisition</i> palette with <i>Digital I/O </i>pointed out</p>
<p class=caption>Figure 25d: <i>Data Acquisition</i> palette with <i>Digital I/O </i>pointed out</p>


<p align=center>[[Image:lab4_55.gif]]</p>
<p align=center>[[Image:lab_labview_55.gif]]</p>


<p class=caption>Figure 4.25e: <i>Digital I/O </i>palette with <i>Advanced Digital I/O </i>pointed out</p>
<p class=caption>Figure 25e: <i>Digital I/O </i>palette with <i>Advanced Digital I/O </i>pointed out</p>


<p align=center>[[Image:lab4_56.gif]]</p>
<p align=center>[[Image:lab_labview_56.gif]]</p>


<p class=caption>Figure 4.25f: <i>Advanced Digital I/O </i>palette with<br>
<p class=caption>Figure 25f: <i>Advanced Digital I/O </i>palette with<br>
<i>Port Config</i> and <i>Port Write</i> circled</p>
<i>Port Config</i> and <i>Port Write</i> circled</p>


<li>Once you have placed these on the <b><i>back panel</i></b>, right click
<li>Once you have placed these on the <b><i>back panel</i></b>, right click
on them and choose <i>View Terminals</i> (Figure 4.26).</li>
on them and choose <i>View Terminals</i> (Figure 26).</li>


<p align=center>[[Image:lab4_57.gif]]</p>
<p align=center>[[Image:lab_labview_57.gif]]</p>


<p class=caption>Figure 4.26: View Terminals</p>
<p class=caption>Figure 26: View Terminals</p>


<li><b><i>Port Config</i></b>. is used to set up the
<li><b><i>Port Config</i></b>. is used to set up the
DAC board for reading or writing, and consists of several terminals.  We are interested in the following five:</li>
DAC board for reading or writing, and consists of several terminals.  We are interested in the following five:</li>


<p align=center>[[Image:lab4_58.jpg]]</p>
<p align=center>[[Image:lab_labview_58.jpg]]</p>
<p class=caption>Figure 4.27: Port Config</p>
<p class=caption>Figure 27: Port Config</p>


<ol>
<ol>
Line 669: Line 670:


<li><b><i>Channel (string):</i></b> This specifies the channel we are using on the DAC board
<li><b><i>Channel (string):</i></b> This specifies the channel we are using on the DAC board
(see Figure 4.4). It can take a value of “2�?, “3�? or “4�?.  Since we are using pins 41 – 47,
(see Figure 4). It can take a value of “2�?, “3�? or “4�?.  Since we are using pins 41 – 47,
wire a string constant of “2�? to the second terminal.</li>
wire a string constant of “2�? to the second terminal.</li>


Line 681: Line 682:


<li><b><i>Task ID Output</i></b>: This specifies what exactly is being output to the DAC
<li><b><i>Task ID Output</i></b>: This specifies what exactly is being output to the DAC
board. Wire this to the Task ID Input terminal on the Port Write (see Figure 4.2).</li>
board. Wire this to the Task ID Input terminal on the Port Write (see Figure 2).</li>
</ol>
</ol>
<li><b><i>Port Write</i></b> is used send information to the DAC board.  It also consists
<li><b><i>Port Write</i></b> is used send information to the DAC board.  It also consists
of several terminals however we are only interested in two.</li>
of several terminals however we are only interested in two.</li>


<p align=center>[[Image:lab4_59.gif]]</p>
<p align=center>[[Image:lab_labview_59.gif]]</p>


<p class=caption>Figure 4.28: Port Write</p>
<p class=caption>Figure 28: Port Write</p>


<ol>
<ol>
Line 727: Line 728:
case and the numeric constant in the False case.</p>
case and the numeric constant in the False case.</p>


<li>4.Also keep in mind that if the master switch is off, then all of the LEDs connected to
<li>Also keep in mind that if the master switch is off, then all of the LEDs connected to
the DAC board should shut off as well.</li>
the DAC board should shut off as well.</li>
</ol>
</ol>
Line 881: Line 882:


<p>Your lab work is now complete. Please clean up your workstation. Return all unused
<p>Your lab work is now complete. Please clean up your workstation. Return all unused
materials to your TA. Refer to section <b><i>4.3 Your Assignment </i></b>for the
materials to your TA. Refer to section <b><i>3 Your Assignment </i></b>for the
instructions you need to prepare your lab report.</p>
instructions you need to prepare your lab report.</p>


Line 891: Line 892:


<ol>
<ol>
<li>On the Controls palette, select the <b>Num Ctrls</b> icon [[Image:lab4_2.gif]]</li>
<li>On the Controls palette, select the <b>Num Ctrls</b> icon [[Image:lab_labview_2.gif]]</li>
<li>Select Horizontal Pointer Slide</li>
<li>Select Horizontal Pointer Slide</li>
<li>Click on the front panel to place the slide on the front panel at the location you select</li>
<li>Click on the front panel to place the slide on the front panel at the location you select</li>
Line 899: Line 900:


<ol>
<ol>
<li>On the Controls palette, select the <b>LEDs</b> icon [[Image:lab4_8.gif]].</li>
<li>On the Controls palette, select the <b>LEDs</b> icon [[Image:lab_labview_8.gif]].</li>


<li>Select the <b>Round LED</b> icon from the icons shown.</li>
<li>Select the <b>Round LED</b> icon from the icons shown.</li>
Line 906: Line 907:


<li>Rename the LED with a label that indicates what the LED stands for. To rename the LED,
<li>Rename the LED with a label that indicates what the LED stands for. To rename the LED,
click on the <b>Edit Text</b> icon [[Image:lab4_10.gif]] on the <b>Tools
click on the <b>Edit Text</b> icon [[Image:lab_labview_10.gif]] on the <b>Tools
palette</b>. Then click on the ‘Boolean’ label on each LED and replace it with
palette</b>. Then click on the ‘Boolean’ label on each LED and replace it with
the proper text.</li>
the proper text.</li>
Line 913: Line 914:
<ol>
<ol>
<li>On the <b>Controls palette</b>, click on the <b>Num Ctrls</b> icon. This will bring up
<li>On the <b>Controls palette</b>, click on the <b>Num Ctrls</b> icon. This will bring up
the window shown in Figure 4.5.</li>
the window shown in Figure 5.</li>


<li>Click on the <b>Num Ctrl</b> icon and click on the location
<li>Click on the <b>Num Ctrl</b> icon and click on the location
Line 921: Line 922:
<h4>How to get a Numeric Indicator Output</h4>
<h4>How to get a Numeric Indicator Output</h4>
<ol>
<ol>
<li>On the Controls palette, click on the <b>Num Inds</b> icon [[Image:lab4_11.gif]].
<li>On the Controls palette, click on the <b>Num Inds</b> icon [[Image:lab_labview_11.gif]].
This will bring up the window shown in Figure 4.9.</li>
This will bring up the window shown in Figure 9.</li>


<li>Click on the <b>Num Ind</b> icon and click on the front
<li>Click on the <b>Num Ind</b> icon and click on the front
Line 934: Line 935:
<ol>
<ol>
<li>In the block diagram (back panel) of LabVIEW, go to the menu bar, select window,
<li>In the block diagram (back panel) of LabVIEW, go to the menu bar, select window,
and choose “Show Functions Palette�?, just as shown on Figure 4.29a. This will bring up
and choose “Show Functions Palette�?, just as shown on Figure 29a. This will bring up
the Functions Palette, shown in Figure 4.29b.</li>
the Functions Palette, shown in Figure 29b.</li>


<p align=center>[[Image:lab4_15.gif]]</p>
<p align=center>[[Image:lab_labview_15.gif]]</p>


<p class=caption>Figure 4.29a: How to bring up the Functions Palette</p>
<p class=caption>Figure 29a: How to bring up the Functions Palette</p>


<p align=center>[[Image:lab4_51.gif]]</p>
<p align=center>[[Image:lab_labview_51.gif]]</p>


<p class=caption>Figure 4.29b: Functions Palette</p>
<p class=caption>Figure 29b: Functions Palette</p>


<li>Clink on the <b>Exec Ctrl</b> icon. This will bring up the <b><i>Exec Ctrl</i></b> window, shown
<li>Clink on the <b>Exec Ctrl</b> icon. This will bring up the <b><i>Exec Ctrl</i></b> window, shown
in Figure 4.13.</li>
in Figure 13.</li>


<li>Click on the <b>Case Structure</b> icon. Click on the right window to locate it on the back panel.</li>
<li>Click on the <b>Case Structure</b> icon. Click on the right window to locate it on the back panel.</li>


<li>4.The default is two cases: 0 and 1. To add more cases, right-click anywhere on the
<li>The default is two cases: 0 and 1. To add more cases, right-click anywhere on the
<b>case structure</b> and select <b>Add Case After</b>, as shown in Figure 4.15.</li>
<b>case structure</b> and select <b>Add Case After</b>, as shown in Figure 15.</li>


<li>Define what happens for each case. On each side of the caption are arrows that will
<li>Define what happens for each case. On each side of the caption are arrows that will
Line 964: Line 965:
<ol>
<ol>
<li>On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>
<li>On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>
icon [[Image:lab4_33.gif]]. will bring up the Arith/Compare window shown
icon [[Image:lab_labview_33.gif]]. will bring up the Arith/Compare window shown
in Figure 4.17.</li>
in Figure 17.</li>


<li>On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab4_24.gif]].
<li>On the Arith/Compare window, click on the <b>Numeric</b> icon [[Image:lab_labview_24.gif]].
This will bring up the <b><i>Express Numeric</i></b> window shown in Figure 4.18.</li>
This will bring up the <b><i>Express Numeric</i></b> window shown in Figure 18.</li>


<li>In the <b><i>Express Numeric</i></b> Window, click on the icon for the arithmetic
<li>In the <b><i>Express Numeric</i></b> Window, click on the icon for the arithmetic
Line 979: Line 980:
<li>On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>
<li>On the <b><i>Functions Palette</i></b>, click on the <b>Arith/Compare</b>


icon [[Image:lab4_33.gif]]. This will bring up the
icon [[Image:lab_labview_33.gif]]. This will bring up the
<b><i>Arith/Compare</i></b> window.</li>
<b><i>Arith/Compare</i></b> window.</li>


<li>On the <b><i>Arith/Compare</i></b> window, click on the <b>Numeric</b> icon
<li>On the <b><i>Arith/Compare</i></b> window, click on the <b>Numeric</b> icon
[[Image:lab4_24.gif]]. This will bring up the <b><i>Express Numeric</i></b> window
[[Image:lab_labview_24.gif]]. This will bring up the <b><i>Express Numeric</i></b> window
shown in Figure 4.18. On the <b><i>Express Numeric</i></b> window, click the
shown in Figure 18. On the <b><i>Express Numeric</i></b> window, click the
upward facing arrow. This will bring up the <b><i>Arithmetic and Comparison</i></b>
upward facing arrow. This will bring up the <b><i>Arithmetic and Comparison</i></b>
window shown in Figure 21.</li>


window shown in Figure 4.21.</li>
<li>On the <b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon
 
[[Image:lab_labview_36.gif]], which will bring up the <b><i>Express Boolean</i></b>
<li>On the <b><i>Arithmetic and Comparison</i></b> window, click on the Boolean icon [[Image:lab4_36.gif]], which will bring up the <b><i>Express Boolean</i></b>
window shown in Figure 22.</li>
window shown in Figure 4.22.</li>


<li>Click on the True Constant icon [[Image:lab4_42.gif]] or False Constant
<li>Click on the True Constant icon [[Image:lab_labview_42.gif]] or False Constant
icon [[Image:lab4_43.gif]], and then clicking the location of the constant
icon [[Image:lab_labview_43.gif]], and then clicking the location of the constant
on the back panel.</li>
on the back panel.</li>


Line 1,003: Line 1,004:
wire the output (right side) of one object to the input (left side) of another object.</li>
wire the output (right side) of one object to the input (left side) of another object.</li>


<li>On the Tools Palette, chose the “Connect Wire�? icon [[Image:lab4_19.gif]].</li>
<li>On the Tools Palette, chose the “Connect Wire�? icon [[Image:lab_labview_19.gif]].</li>


<li>Click the object output that you want to wire from. Click the object input you want to
<li>Click the object output that you want to wire from. Click the object input you want to
Line 1,010: Line 1,011:




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Revision as of 19:38, 10 August 2005

EG1004 Lab 4: Introduction to LabVIEW

1 OBJECTIVES

The experimental objective of this lab is to design three systems using LabVIEW:

  1. A digital calculator
  2. A lighting system for a building
  3. A thermal control system that automatically turns on heating and cooling equipment

Building these systems allows us to investigate the potential for using simulated instruments in the laboratory. These programs will let you to obtain data from outside the computer and incorporate it into your program design. In contrast to the more common text-based languages, LabVIEW uses a graphical programming language. You will learn the logic of graphical programming during the course of this lab.

2 OVERVIEW

Adapted from Introduction to LabVIEW, Six-Hour Course.10

LabVIEW is a development environment for creating graphical programs, called virtual instruments (VIs), to simulate actual laboratory instruments. A VI consists of two parts: a front panel and a back panel. The front panel allows the user to interact with the VI by displaying output and allowing the user to supply the program with input. The back panel consists of the actual code used by the VI to obtain input from the front panel, operate on the input, and display the results.

The front panel is built using controls and indicators. Controls are inputs – they allow a user to supply information to the VI. Indicators are outputs – they indicate, or display, the results based on the inputs given to the VI. Controls consist of switches, knobs, dials, buttons, etc. and indicators consist of meters, gauges, LEDs, displays, etc. These are located on the Controls palette and can be placed on the front panel.

The back panel, which is a block diagram, contains the graphical source code. All of the objects placed on the front panel will appear on the back panel as terminals. The back panel also contains structures and functions which perform operations on controls and supply data to indicators. The structures and functions are found on the Functions palette and can be placed on the back panel. Collectively controls, indicators, structures and functions will be referred to as nodes. Nodes are connected to one another using wires – e.g. two controls and an indicator can be wired to the addition function so that the indicator displays the sum of the two controls.

In any programming language, structures allow you to create conditions. In LabVIEW you can access structures by opening the Functions palette and selecting Structures. The following are some examples of structures:

  1. The While Loop is similar to do loop or while in text-based programming languages. It executes its subdiagram (or subroutine) until it receives a false value.
  2. The For Loop executes a subdiagram a set number of times, specified by the value in the count terminal.
  3. The Case Structure is similar to if/else, switch/case or match/with in text-based programming languages. It contains multiple subdiagrams – one for each possible value of the input to the case structure (the control wired to the ‘?’).

The data acquisition and control (DAC) board is LabVIEW’s physical interface with the outside world. To send or receive data through the board, you must specify two parameters: the device number and the channel. For our purposes, the device number is 1. When there is more than one DAC board attached to a computer, the device number specifies which DAC board to use. The channel input specifies which channel on the DAC board to read. There is one DAC board for analog data and another digital data. The analog board uses pin 1 for ground and pins 3-18 for analog I/O (input/output). The digital board uses even-numbered pins for ground and odd-numbered pins 1-47 for digital I/O. Pin 49 is a constant output of +5 VDC. For convenience, always use pin 50 as your ground.

Some useful key shortcuts to keep in mind when working in the LabVIEW environment:

  1. CTRL+H: Show/hide context help.
  2. CTRL+B: Clean up broken wiring.
  3. CTRL+E: Toggle between front/back panels.
  4. CTRL+Z: Undo last action.

3 YOUR ASSIGNMENT

Team PowerPoint Presentation and Individual Lab Report

Follow the lab report guidelines laid out in the section called Specifications for Writing Your Lab Reports in the Technical Communication section of this online manual.

IMPORTANT: Because the procedural elements in this lab are extensive, please include only the procedures you employed to build Design 2, the Heating and Cooling System in your lab report. You do not need to document the procedures you followed to build Design 1, the Simple Calculator.

Remember, your job in this lab is not to report whether the Heating and Cooling system worked. Your job is to report on what you did to design it. Please consider the value of LabVIEW as a substitute for actual instruments and systems. Your Data/Observations section should include information on ease of use, the LabVIEW user interface, and the help options available to you.

As you write, the following discussion points should be addressed in the appropriate section of your lab report and in your PowerPoint presentation:

  • Explain what LabView is and describe how it helps engineers and scientists with their work.
  • Explain what a VI is.
  • What is the Front Panel used for? The Back Panel?

4 MATERIALS AND EQUIPMENT

  • Lab PC
  • LabVIEW Software
  • Data Acquisition and Control (DAC) Board
  • Breadboard
  • Several LEDs

5 PROCEDURE

  1. Open LabVIEW, select New and Blank VI.
  2. Click on Window and select Tile Left & Right to set the front panel (left window) and back panel (right window) side by side. This will make them visible at the same time, making it easier to work.
  3. On the right window, pull down the Window menu, select Show Tools Palette.
  4. On the left window, pull down the Window menu again, select Show Controls Palette. At this point your screen should look like Figure 3. Note the Controls Palette and the Tools Palette, and their icons.

Lab labview 1.gif

Figure 3: LabVIEW workspace

Remember: You are required to take notes. Experimental details are easily forgotten unless written down. You should keep a laboratory notebook for this purpose. Use your lab notes to write the Procedure section of your lab report. You must attach a copy of your lab notes to the WC copy of your lab report. Keeping careful notes is an essential component of all scientific practice.

For help with the operation of any LabVIEW icon, select Help from the main menu bar, choose Show Context Help, and click the icon whose operation you don't understand. It will be explained in the open window.

The overall approach for each of these projects is to place items on the front panel that the user will see and interact with. The corresponding items on the back panel will then actually make the device work, and how you “wire�? them together will determine how your device works.

Note: We’ll be doing some tasks a number of times, where you’ll be clicking on the same icons to bring up various components. To help you , we’ve included a LabVIEW digest at the end of this lab for your reference to help you navigate.

Design 1: Simple Calculator

Create a program that simulates a basic calculator. Your calculator will be able to add, subtract, and multiply.

  1. The front panel must contain:
    1. One slide to control the arithmetic operation to be performed. Here’s how to do it:
      1. Select the Num Ctrls icon Lab labview 2.gif on the Controls Palette (see Figure 4). This will bring up the window shown in Figure 5

        Lab labview 3.gif

        Figure 4: Controls Palette

        Lab labview 5.gif

        Figure 5: Numerical Controls window

      2. Then select Horizontal Pointer Slide from the icons shown. Click on the left window to place the slide on the front panel at the location you select.
      3. Note: If you don’t like where you put the slide, click on it and hold down the left mouse button to “drag�? the control where you want it. When it’s at the right place, let go of the left mouse button. This will work for everything you do on both windows (front and back panels).

        Note: As you place items on the front panel (left window), symbols corresponding to each item will appear on the back panel (right window). After we complete the front panel, we’ll wire the items on the back panel to make the calculator work.

      4. Click on the number 10 and change it to 2. Now the slide control will look like Figure 6.
      5. Lab labview 6.gif

        Figure 6: Slide control with range changed from 10 to 2

      6. Right click on the slide to bring up a pull down menu. Select Representation, and choose the I32 icon. Figure 7 shows what the pull down menus look like, and the I32 icon. This completes the slide control on the front panel.
      7. Lab labview 7.gif

        Figure 7: I32 Representation pull down menus

    2. Three Boolean indicators to specify the operation selected. Here’s how to do it:
      1. On the Controls palette, select the LEDs icon Lab labview 8.gif. This will bring up the window shown in Figure 8.
      2. Lab labview 9.gif

        Figure 8: LEDs Window

      3. Select the Round LED icon from the icons shown. Click on the left window to place the LED on the front panel at the location youh select. The best place to put it is centered under the slide. Do this two more times, putting the lights on each side of the first light you made, so you have a total of three lights in a row under the slide.
      4. Rename the three LEDs to correspond to the functions the calculator will be performing: add, subtract, and multiply. To rename each LED, click on the Edit Text icon Lab labview 10.gif on the Tools palette. Then click on the ‘Boolean’ label on each LED and replace it with the proper text: “add�? for the left light, “subtract�? for the center light, and “multiply�? for the right light.
    3. Two numeric controls to allow the user to input data from the keyboard. Here’s how to do it:
      1. On the Controls palette, click on the Num Ctrls icon. This will bring up the window shown in Figure 5 again.
      2. Click on the Num Ctrl icon and click on the left window to the left of the slide to place a numeric control there. This will look like a window you can enter data in. Click the Num Ctrl icon again, and place another numeric control on the right side of the slide.
    4. A numeric indicator to display the output. Here’s how to do it:
      1. On the Controls palette, click on the Num Inds icon Lab labview 11.gif. This will bring up the window shown in Figure 9.
      2. Lab labview 12.gif

        Figure 9: Num Inds Window

      3. Click on the Num Ind icon and click on the left window centered below the three lights. This numeric indicator will be the answer from the calculator.
      4. Note: This numeric indicator, used for output, is a different type of object from the two numeric controls (which are for input) that you constructed earlier in Item c.

      5. You are now finished constructing the front panel. The finished Front Panel should look like Figure 10:

    Lab labview 13.gif

    Figure 10: Finished Front Panel

    As we stated earlier, on the back panel there are icons corresponding to everything you put on the front panel. We will now arrange them, add additional objects, and connect them together to make the calculator work.

  2. The back panel must contain:
    1. At least one case statement to control the arithmetic operations. This case statement will be the heart of the calculator. Here’s how you do it:
      1. Drag all the Boolean nodes to the right edge of the window and all numeric controls and indicator to the bottom of the window. Place the slide node on the left edge of the window. This will leave a large area in the middle that you will fill in at the next few steps. Your back panel should now look like Figure 11.
      2. Lab labview 14.gif

        Figure 11: Rearranged Back Panel

      3. In the block diagram (back panel) of LabVIEW, go to the menu bar, select window, and choose “Show Functions Palette�?, just as shown on Figure 12a. This will bring up the Functions Palette, shown in Figure 12b.
      4. Lab labview 15.gif

        Figure 12a: How to bring up the Functions Palette

        Lab labview 16.gif

        Figure 12b: Functions Palette

      5. Clink on the Exec Ctrl icon Lab labview 17.gif. This will bring up the Exec Ctrl window, shown in Figure 13.
      6. Lab labview 18.gif

        Figure 13: Exec Ctrl Window

      7. Click on the Case Structure icon. Click on the right window to locate it on the back panel. Be careful, it’s a very large object, and will have many connections. Your best strategy is to locate it in the middle of the panel. Note that at the top of the object there a caption box with the number 1 in it. On each side of the caption box are arrows pointing to the left and right. Note also the question mark on the left side of the case structure object. This is the input to the case structure.
      8. We will now start connecting things. First, we need to access the proper tool. On the Tools Palette, chose the “Connect Wire�? icon Lab labview 19.gif. We’ll now connect the slide to the case structure. Connect the slide to the case structure by clicking on the slide object, and then on the question mark on the left side of the case structure. Your back panel should now look like Figure 14.
      9. Lab labview 20.jpg

        Figure 14: Back Panel Slide to Case Structure Connection

      10. When the case statement is created, it only has two cases. Since you have three operations for the calculator, you need to make another case. To add the third case operation, right-click anywhere on the case structure and select Add Case After, as shown in Figure 15.
      11. Lab labview 21.gif

        Figure 15: Adding Another Case

      12. Now we’ll add the mathematical operations that the calculator should perform for each case. On the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif from the main Functions Palette. This will bring up the Arith/Compare window shown in Figure 17.
      13. Lab labview 23.gif

        Figure 17: Arith/Compare Window

      14. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18.
      15. Lab labview 25.gif

        Figure 18: Express Numeric Window

      16. Click on the left arrow at the top of the case structure box. This should change the caption for the case structure to 0. In the Express Numeric Window, click on the Add icon Lab labview 26.gif, and click on a location in the middle of the case structure box to place it.
      17. Click on the right arrow at the top of the case structure box. This should change the caption for the case structure to 1. In the Express Numeric Window, click on the Subtract icon Lab labview 27.gif, and click on a location in the middle of the case structure to place it.
      18. Finally, click on the right arrow at the top of the case structure box one more time, changing the number in the caption to 2. In the Express Numeric Window, click on the Multiply icon Lab labview 28.gif, and click on a location in the middle of the case structure to place it. At this point, each case should look like the ones shown in Figure 19. You can check each case by clicking on the left and right arrows to change the case number in the caption.
      19. Lab labview 29.gifLab labview 30.jpgLab labview 31.gif

        Figure 19: Case Structure Cases

      20. We now need to wire the inputs of the calculator. First, set the case structure case to zero by clicking on the left arrow until the caption reads 0. The triangle inside should be addition, with a plus sign in the middle. Once again, click on the “Connect Wire�? icon Lab labview 19.gif on the Tools Palette. Click on the leftmost Numeric icon, and click on the top left side of the operation triangle to wire the first numeric input to the input of the addition operation. Next, click on the second numeric icon, and on the left bottom of the addition triangle, establishing the second input. Finally, click on the right side of the triangle, and click on the third Numeric icon. This will display the output of the addition calculation in the “Numeric 3�? box on the front panel. At this point you’ve completed having the calculator do addition. Your back panel should look like Figure 20.
      21. Lab labview 32.gif

        Figure 20: Completed Back Panel for Addition

      22. We now have to do the same thing for the other cases. Click on the right arrow next to the case structure caption. This will change the caption to 1, and the subtraction triangle will be in the middle of the case structure. As before, connect the first Numeric object to the top left of the triangle, the second Numeric to the bottom left of the triangle, and the right of the triangle to the Numeric 3 box at the bottom of the back panel. You can see the preceding step for details on how to do this if you need to. Finally, click the right arrow next to the case structure caption one more time. This will change the case number to 2, and the multiplication triangle will be in the middle of the case structure. Wire the Numeric objects to the triangle as you did for the other two case. At this point you have established the numeric inputs and outputs.
      23. We now to have to illuminate the proper LED on the front panel corresponding to each operation. First, click the left arrow to the left of the caption of the case structure until the caption says “0, Default�?. First, we’re going to repeat Steps 7 and 8 to bring up the Express Numeric window: On the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif from the main Functions Palette. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18. On the Express Numeric window, click the upward facing arrow. This will bring up the Arithmetic and Comparison window shown in Figure 21.
      24. Lab labview 23.gif

        Figure 21: Arithmetic and Comparison Window

      25. On the Arithmetic and Comparison window, click on the Boolean icon Lab labview 36.gif, which will bring up the Express Boolean window shown in Figure 22.
      26. Lab labview 37.gif

        Figure 22: Express Boolean Window

      27. We are now going to put three Boolean constants into the case structure. Since this is case 0, which corresponds to add, we want to have the add indicator to be true, and the other two to be false. We do this by clicking on the True Constant icon Lab labview 42.gif, and then clicking inside the case structure on the right side to the left of the add indicator that’s outside the case structure. We then select the False Constant icon Lab labview 43.gif and place it inside the case structure on the right side next to the Subtract and Multiply indicators.
      28. We now need to wire the constants to their respective indicators. Once again, click on the Connect Wire icon Lab labview 19.gif on the Tools Palette. Click on the right side of the top constant inside the case structure and connect it to the top indicator by clicking on the indicator next. Then do the same thing for the other two constants and their corresponding indicators. We’ve now completed the Add operation. We still need to do the other two operations.
      29. Click on the right arrow next to the case structure icon. The caption should now show 1. We need to have the Subtract indicator illuminate for this case. Once again, on the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif from the main Functions Palette. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18. On the Express Numeric window, click the upward facing arrow. This will bring up the Arithmetic and Comparison window shown in Figure 21. On the Arithmetic and Comparison window, click on the Boolean icon Lab labview 36.gif, which will bring up the Express Boolean window shown in Figure 22.Click on the True Constant icon Lab labview 42.gif and click inside the right side of the case structure to the left of the Subtract LED. Click on the False Constant icon Lab labview 43.gif and click inside the right side of the case structure to the left of the Add LED, and again to the left of the Multiply LED. Click on the Connect Wire icon Lab labview 19.gif on the Tools Palette. Click on the right side of the top constant inside the case structure and connect it to the top indicator by clicking on the indicator next. Then do the same thing for the other two constants and their corresponding indicators. We’ve now completed the Subtract operation.
      30. We’re now ready to finish the calculator. Click on the right arrow next to the case structure icon. The caption should now show 2. We need to have the Subtract indicator illuminate for this case. Once again, on the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18. On the Express Numeric window, click the upward facing arrow. This will bring up the Arithmetic and Comparison window shown in Figure 21. On the Arithmetic and Comparison window, click on the Boolean icon Lab labview 36.gif which will bring up the Express Boolean window shown in Figure 22. Click on the True Constant icon Lab labview 42.gif and click inside the right side of the case structure to the left of the Subtract LED. Click on the False Constant icon Lab labview 43.gif and click inside the right side of the case structure to the left of the Add LED, and again to the left of the Multiply LED. Click on the Connect Wire icon Lab labview 19.gif on the Tools Palette. Click on the right side of the top constant inside the case structure and connect it to the top indicator by clicking on the indicator next. Then do the same thing for the other two constants and their corresponding indicators. We’ve now completed the Multiply operation.
      31. Before moving on, make sure that the boxes on the edges of the case structure are filled in. If they are not, that box has to be wired in all cases defined by the user. Your back panel should look like Figure 23.
      32. Lab labview 48.gif Lab labview 49.jpg

        Figure 23: Completed Calculator Back Panel

  3. After you have created your VI, it must be tested:
    1. Enter different input numbers through the control icon on the front panel.
    2. Make sure the output is correct.
    3. Make sure the correct LED lights up for the operation.
    4. Have your TA test your VI.

    Lab labview 50.gif

    Figure 24: Completed and Working VI

  4. Once testing is completed:
    1. Print the VI you have created.
    2. Have your TA sign it.

Design 2: Heating and Cooling System

Build a VI that simulates a heating and cooling system. Your system must be controlled either manually or automatically. Design your VI so that:

  • The air conditioner is turned on when the temperature is above 80°F.
  • The heater is turned on when the temperature is less than 60°F.
  • The heater and the air conditioner are turned off when the temperature is between 60°F and 80°F.
  1. The front panel must contain:
    1. Three LEDs: one to represent the AC, one to represent the heater, and one to show that the system is being operated manually.
    2. Three switches: one to control the AC, one to control the heater, and one to control manual or automatic operation.
    3. A thermometer to set the temperature of the system. The thermometer should be set to 70°F.
  2. The back panel must contain:
    1. A Boolean case statement to control the manual and automatic operation of the AC and the heater.


  3. After you have created your VI, it must be tested:
    1. Using the slide bar on the thermometer, change the system temperature. Make sure the AC and heat come on as directed.
    2. Test the program’s manual operation by turning the manual switch on and then turning the AC and heat switches on. Each of the LEDs should light up when its corresponding switch is in the On position.
    3. Have your TA test your VI.
  4. Once testing is completed:
    1. Print the VI you have created.
    2. Have your TA sign it.
    3. Save your VI. You'll be using it again in Lab 6.

Design 3: Lighting System

Build a VI that simulates a lighting system in a house with 4 rooms. Your design must include 4 lights (LEDs) and at least 5 switches – one switch per light and one “master�? switch which will turn all of the lights off simultaneously (think of this as a circuit breaker). Your program should also interact with real LEDs attached to a DAC board.

  1. The front panel of your program should include 5 switches and 4 virtual LEDs.
  2. While there are several ways to implement the back panel, one suggestion is to use a separate Boolean case structure for each switch. This will also make it easier to interact with the LEDs attached to the DAC board.
  3. In order to control the LEDs attached to the DAC board, a Port Configuration and a Port Write node are required on the back panel. The LEDs will be connected to pins 47, 45, 43 and 41 (and pin 50 for ground).
    1. Port Config. and Port Write are found in the Functions Palette, under All Functions -> NI Measurements ->Data Acquisition -> Digital I/O -> Advanced Digital I/O. (see Figures 25a-f)
    2. Lab labview 51.gif

      Figure 25a: Functions Palette

      Lab labview 52.gif

      Figure 25b: All Functions palette with NI Measurements pointed out

      Lab labview 53.jpg

      Figure 25c: NI Measurements palette with Data Acquisition pointed out

      Lab labview 54.gif

      Figure 25d: Data Acquisition palette with Digital I/O pointed out

      Lab labview 55.gif

      Figure 25e: Digital I/O palette with Advanced Digital I/O pointed out

      Lab labview 56.gif

      Figure 25f: Advanced Digital I/O palette with
      Port Config and Port Write circled

    3. Once you have placed these on the back panel, right click on them and choose View Terminals (Figure 26).
    4. Lab labview 57.gif

      Figure 26: View Terminals

    5. Port Config. is used to set up the DAC board for reading or writing, and consists of several terminals. We are interested in the following five:
    6. Lab labview 58.jpg

      Figure 27: Port Config

      1. Device Line (integer): This tells the VI which DAC board to use. As stated in the overview, the DAC board has a device number of 1, so wire a numeric constant of 1 to the first terminal.
      2. Channel (string): This specifies the channel we are using on the DAC board (see Figure 4). It can take a value of “2�?, “3�? or “4�?. Since we are using pins 41 – 47, wire a string constant of “2�? to the second terminal.
      3. Port Width (integer): This determines the number of pins used by each channel. It is a multiple of 8. Since we are only using 4 pins, wire a numeric constant of 8 to the third terminal.
      4. Line Direction (integer): This tells the DAC board whether it is writing (-1) or reading (0). Since we are outputting (writing) to the DAC board, wire a numeric constant of -1 to the fourth terminal.
      5. Task ID Output: This specifies what exactly is being output to the DAC board. Wire this to the Task ID Input terminal on the Port Write (see Figure 2).
    7. Port Write is used send information to the DAC board. It also consists of several terminals however we are only interested in two.
    8. Lab labview 59.gif

      Figure 28: Port Write

      1. Task ID Input: this is wired to the Task ID Output terminal on the Port Config.
      2. Pattern (integer): This determines which pins on the DAC board will be activated (in other words, which LEDs will light up).
        1. Each pin is represented by a number that is a power of 2 (see Pattern Table). For example, sending a value of 1 will light up the LED connected to pin 47.
        2. To light up more than one pin at a time, add the values of each pin together and use the sum. For example, sending a value of 3 to the Pattern will result in the LEDs connected to pins 47 and 45 to light up.
    9. If you used separate Boolean case structures for each switch, then setting up the pattern for Port Write can be achieved as follows:
      1. In each Boolean case, if the switch is off, place a numeric constant of 0.
      2. If the switch is on, then include a numeric constant of the appropriate value (see Pattern Table). For example, the switch corresponding to pin 47 should have a numeric constant of 1.
      3. Once every Boolean case structure has a numeric constant in it, they must all be added together. This can easily be achieved using the Compound Arithmetic operator. The output from the Compound Arithmetic operator should be wired to the Pattern on Port Write.
      4. Don’t forget to wire both the numeric constant in the True case and the numeric constant in the False case.

      5. Also keep in mind that if the master switch is off, then all of the LEDs connected to the DAC board should shut off as well.

Pattern Table

Pattern

 

128

64

32

16

8

4

2

1

Channel

Corresponding Pin Number (for Port Width of 8)

2

33

35

37

39

41

43

45

47

3

17

19

21

23

25

27

29

31

4

1

3

5

7

9

11

13

15

Your lab work is now complete. Please clean up your workstation. Return all unused materials to your TA. Refer to section 3 Your Assignment for the instructions you need to prepare your lab report.

LabVIEW Digest of Common Tasks

Front Panel Controls and Indicators

How to get a slide control:

  1. On the Controls palette, select the Num Ctrls icon Lab labview 2.gif
  2. Select Horizontal Pointer Slide
  3. Click on the front panel to place the slide on the front panel at the location you select

How to get a LED indicator:

  1. On the Controls palette, select the LEDs icon Lab labview 8.gif.
  2. Select the Round LED icon from the icons shown.
  3. Click on the left window to place the LED on the front panel at the location you select.
  4. Rename the LED with a label that indicates what the LED stands for. To rename the LED, click on the Edit Text icon Lab labview 10.gif on the Tools palette. Then click on the ‘Boolean’ label on each LED and replace it with the proper text.

How to get a Numeric Input Control

  1. On the Controls palette, click on the Num Ctrls icon. This will bring up the window shown in Figure 5.
  2. Click on the Num Ctrl icon and click on the location where you want to place the control.

How to get a Numeric Indicator Output

  1. On the Controls palette, click on the Num Inds icon Lab labview 11.gif. This will bring up the window shown in Figure 9.
  2. Click on the Num Ind icon and click on the front panel location where you want the indicator.

Back Panel Objects

How to define a case structure

  1. In the block diagram (back panel) of LabVIEW, go to the menu bar, select window, and choose “Show Functions Palette�?, just as shown on Figure 29a. This will bring up the Functions Palette, shown in Figure 29b.
  2. Lab labview 15.gif

    Figure 29a: How to bring up the Functions Palette

    Lab labview 51.gif

    Figure 29b: Functions Palette

  3. Clink on the Exec Ctrl icon. This will bring up the Exec Ctrl window, shown in Figure 13.
  4. Click on the Case Structure icon. Click on the right window to locate it on the back panel.
  5. The default is two cases: 0 and 1. To add more cases, right-click anywhere on the case structure and select Add Case After, as shown in Figure 15.
  6. Define what happens for each case. On each side of the caption are arrows that will count the case number up and down. Choose the case number you want to define and then fill in the case structure with whatever needs to be done for this case. Make sure every case is fully defined. It is very easy to forget things.

How to define an arithmetic operation

  1. On the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif. will bring up the Arith/Compare window shown in Figure 17.
  2. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18.
  3. In the Express Numeric Window, click on the icon for the arithmetic operation you want. Click on the front panel location where the icon goes.

How to define Boolean constants (usually used to illuminate LEDs)

  1. On the Functions Palette, click on the Arith/Compare icon Lab labview 33.gif. This will bring up the Arith/Compare window.
  2. On the Arith/Compare window, click on the Numeric icon Lab labview 24.gif. This will bring up the Express Numeric window shown in Figure 18. On the Express Numeric window, click the upward facing arrow. This will bring up the Arithmetic and Comparison window shown in Figure 21.
  3. On the Arithmetic and Comparison window, click on the Boolean icon Lab labview 36.gif, which will bring up the Express Boolean window shown in Figure 22.
  4. Click on the True Constant icon Lab labview 42.gif or False Constant icon Lab labview 43.gif, and then clicking the location of the constant on the back panel.

How to wire things

  1. Objects have inputs on their left side and outputs on their right side. You always wire the output (right side) of one object to the input (left side) of another object.
  2. On the Tools Palette, chose the “Connect Wire�? icon Lab labview 19.gif.
  3. Click the object output that you want to wire from. Click the object input you want to wire to. The first object’s output is now connected to the second object’s input.


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