Lab 7: Labview Tutorial By Joseph Gamble 

 

 

 

 

Intro In this document I will outline labview techniques that can be used in 

the generation of a labview test script for lab 7. Purpose is to provide students 

with a satisfactory guide to complete the automated testing environment for 

lab 7 in ee330. The document will cover every single step in order to replicate 

the code in case edits need to be made.  

 

 

 

   

 

 

 

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Labview Flows 

What Was Needed 

In this section the steps in the generation of the labview code. Labview 

is a visual software environment from National Instruments. It is expected to 

be supported by National Instruments for quite a while and therefore can be 

utilized within the EE 330 lab space for some time. It should be noted that 

this tutorial has been developed for the 2019 version of the software. It is 

unclear how the future version will work. The instructions will have pictures 

intermittent throughout to aid in the explanation process. 

What I Did 

Find the “NI Labview 2019 (64-bit)” application on your computer and 

open it. When the labview program first boots up, you have a screen where 

you can select between opening up a new project or existing old project. 

 

 Opening Selection Menu to Select Between Old and New Projects 

 

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In order to open a new project that can be run with the instruments, 

click “Create Project” and select “Blank VI”. VI stands for virtual instrument 

and allows you to connect to the bench instruments like power supply, 

multimeter, etc. and edit their input and output to record data. After 

selecting a blank VI project, two windows should pop up. One is the “Front 

Panel” which houses the communication to outside devices and the other is 

the “Block Diagram” which holds the way your program is run. On your 

Front Panel right click and select “Classic > I/O > VISA Resource”. This allows 

you to establish communication with the lab equipment. We will say that this 

one is for the dc power supply. Double click the “Visa Resource Name” above 

the I/O port to edit the name to whatever you want to call the DC power 

supply. Note that the Block Diagram now has a VISA block. 

 

 Selecting a New Instrument Block 

 

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We will now spend a good portion of time in the Block Diagram screen, 

organizing our test flow. Let’s add a block to initialize the power supply to set 

it up for communicating. Right click and go “Instrument I/O > Istr Drivers > 

Agilent E363X >Initialize”. This allows you to place an initialization block into 

the diagram. On the left side of your newly placed block there should be a 

“VISA Resource Name” node that pops up when the cursor hovers over the 

block so connect that line with your VISA I/O block.  

Congrats! You have now programmed something in labview. Now we 

need to set the serial interface for the DC power supply from this initialization 

block. Right click the top port of the initialization block called “Serial 

Configuration” and select “Create Control” which creates a serial 

configuration block in your Front Panel. We won’t worry about it right now 

and continue to develop our logic flow. 

 

 Selecting an initialization block 

 

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Now generate a for loop. This will be where we sweep the Vgs value. 

“Right Click > Structures > For Loop”. Go ahead and place a second For loop 

inside the first. The interior for loop is for editing the Vds value.  

 

 Generating the For Loops 

 

Right click the “N” in the upper left hand corner of the exterior for loop 

and select “Create Constant”. This will set the number of iterations of the 

loops. For the Vgs we are sweeping from .5V to 2.5V in steps of .5, so 5 

iterations are required. In the inner loop we require a sweep from 0V to 2.5V 

in steps of .05V so 51 iterations are required. Change the number of iterations 

in the 2 loops accordingly. 

Now we need to set two configuration blocks into the two for loops, 

one for Vds and the other for Vgs. These will be the block that tell the DC 

output voltage what to be. To get the block do “Right Click > Instrument I/O 

> Istr Drivers > Agilent E363X > Configure > Output”. This block has several 

lines in it that we need to connect. One is the “Voltage Level Line”. It needs 

to be set according to the iteration which is held in the “i” block in the lower 

left hand of the for loop. This can be done by placing numeric blocks (“Right 

Click > Numeric”) within the Block Diagram with the correct logic to output 

the correct voltage value (indexing starts at 0 in labview!!!). [HINT: Add 

 

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numeric constant blocks to set values.] Do this for both the Vds and Vgs lines. 

Also connect the “error in (no error)” line from the configure block to the 

“error out” of your initialize block and the “visa resource name” of the 

configure block to the “visa resource name out” of the initialization block. By 

the end, your Block diagram should look something like this: 

 

 Configuration Blocks Placed with Iteration Logic 

 

The configuration blocks correspond to two of your outputs on your 

agilent E3631A, but you need to inform the code configuration block which is 

which voltage input. For the sake of simplicity say the Vds is the +6 voltage 

supply and the Vgs is your +25V (but they could be switched). If you hover 

over and right click the left side of the configure block called “Channel (1: 

 

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Channel 1” and select “Create Constant” a selection should appear 

connected to the line that says Channel 1. The conversion from output line on 

the voltage supply to channel number is +6 = Channel 1, +25 = Channel 2, -25 

= Channel 3. For our sake, then the Vds control (internal for loop) will be 

Channel 1, and the Vgs (outer loop) will be Channel 2.  

We will need to close our connection to the voltage supply after we are 

done running our sweep. By doing “Right Click > Instrument I/O > Istr 

Drivers > Agilent E363X > Close” we can place a close block for the voltage 

supply. Make sure it is placed outside of both of your for loops. Connect the 

“error in (no error)” line from the close block to the “error out” of your Vds 

configure block and the “visa resource name” of the close block to the “visa 

resource name out” of the configure block. The lines will error as they leave 

the for loop as the program doesn’t know how to handle a single value being 

passed out of multiple iterations. Find the little boxes of the lines as they exit 

the for loop “Right Click > Tunnel Mode > Last Value” which sets the data to 

transfer at the end of the for loop iterations (when we want to close the 

device). Your Block Diagram should now look like this: 

 All of Voltage Supply Components in Block Diagram 

 

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At this point all of the components for the voltage supply are in the 

Block Diagram open up the Front Panel which should still be open. The 

“Serial Configuration” in the Front Panel that we created a while back 

should be set right, but be sure Baud = 9600, Parity = 0, and data bits = 8. Now 

we are going to make our second VISA resource, the multimeter. Again 

“Classic > I/O > VISA Resource” and rename it to multimeter, or something 

along those lines. A Visa Resource will appear in your Block Diagram. Go back 

to your Block Diagram to begin routing your multimeter lines. 

Generate another initialization block by doing “Instrument I/O > Istr 

Drivers > Agilent E3446X >Initialize”. Note this is a different driver selection 

then last as we are selecting a different bench device. Now place a block to 

configure the multimeter to DC Current by using “Right Click > Instrument 

I/O > Istr Drivers > Agilent E3446X > Configure > Measurement > Configure 

Measurement” to place the block. After this route the “error in” and “VISA 

resource name” lines between configure and initialize blocks as had been 

done with the DC voltage supply. Here’s a look as to what the block diagram 

should look like now: 

 Initialization Block within the Block Diagram 

 

 

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On the configure block in your main Block Diagram page we need to 

set the current range on the digital multimeter. If we don’t, the multimeter 

jumps varying ranges, creating jumps in our output waveform. 

So, on the “Measurement Function” of the multimeter configure block 

“Right Click > Create Constant” which should make a selection menu pop 

up. Select “DC Current” from this menu (as we want the multimeter to read 

current). On “Autorange”, “Right Click > Create Constant” and click on the 

appeared “T” to make it “F” to enable manual current range mode. Now we 

need to set the current range by finding “Manual Range” on the same block 

and on it doing “Right Click > Create Constant” and setting that constant to 

.01 (10mA). By the end of all of this the Block Diagram should look like this: 

 

 Block Diagram with Multimeter Initialization and Configuration 

 

Now that the block setup is done for the multimeter we can setup the 

data taking portion of the Block Diagram. Place a “Data.vi” block by taking 

 

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“Right Click > Instrument I/O > Istr Drivers > Agilent E3446X > Data > 

Read.vi” and placing it within the interior loop. Connect its “error” pin and 

“VISA resource name” pin to the multimeter configure block. Sweet! Now 

we can take measurements! However, we don’t know whether we are 

changing the value for the dc power supply or taking reads first within the 

loop. Let's ensure there is no confusion by placing a “Flat Sequence” around 

the two conditions. Find the structure by doing “Right Click > Structure > 

Flat Sequence” and place it within the interior loop, moving the configure 

into the flat sequence too. Now on the flat sequence “Right Click > Add 

Frame After” and place the data read in the second frame. After all this the 

Block Diagram should look like this: 

 

 Block Diagram with Reads and Vds Configuration within Sequence Frames 

 

This structure will come out as a single value, and we need a way to 

analyze the data as a chunk. Let’s format the individual chunks into a .csv file 

(comma separated values). “Right Click > File I/O > Write Delimited 

 

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Spreadsheet.vi” to create the “Write Delimited Spreadsheet.vi” block. On 

the pin out of the block, for delimiter “Right Click > Create Constant” and 

set the delimiter to “,”. For “Format”, “Right Click > Create Constant” and 

set the value to “%.12f”. Finally, for “Transpose”, “Right Click > Create 

Constant” and set the value to “T”.  

We also need to drop a block to build the array for the data going into 

the file generator, so create “Build Array” by following “Right Click > Arrays 

> Build Array”. Route the right side of this build array block into the 

spreadsheet writing block and under the “2D Data” pin. Route the left side of 

the array building block into both of the For loops into the “Measurement” 

pin of the “Read.vi” block. The tunneling of the measurements through the 

for loops is a bit tricky. Change the interior loop tunneling to “indexing” and 

the outer loop tunneling to “concatenating”. The Block Diagram should now 

look like this: 

 

 Block Diagram with .csv File Generating Blocks 

 

 

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The final action we need to take within the block diagram is to close the 

multimeter. Create the “Close” block by doing “Right Click > Instrument I/O 

> Istr Drivers > Agilent E3446X > Close”. Place the close block on the outside 

of the for loops and route it’s relative “VISA resource name” and “error” to 

the “Read.vi” block. It will be upset as the two lines pass through two for 

loops. Change their tunneling mode to “Last Value” and they should be 

happy. The final Block Diagram should look like this: 

 

 Final Block Diagram 

 

Congrats! We are done with the Block Diagram! There is still something 

to be done in the front panel. Turn on both your multimeter and Voltage 

source. Go to the I/O selection window in the front panel and select the 

channel address your devices are on. I have found it best to turn the 

multimeter on and off, looking for the channel that opens and closes, while 

the address of the voltage source can be found by selecting the “I/O config” 

button on the bench device. Your front panel should now look like this: 

 

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Hooray! You are all ready to run. Click the “Run” button in the top 

toolbar. It looks like a small arrow pointing to the right. The values on the 

multimeter and voltage source should flip around. The entire sweep should 

take approximately 5 minutes to complete so have  

a nice chat with the person next to you.  

After the test is completed, a window should pop up letting you save 

your new output file. Name is something reasonable and be sure to terminate 

the name with a .csv for it can be opened with Excel. Good job! You have now 

swept the value of Vds over various Vgs values for your MOSFET transistor. 

 

 

   

 

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Appendix 

Colors 

Each color within the lab view is a reference to a different bus/data type. Here 

are a few colors that may be helpful: 

 

Error Bus:  

Integer Value:  

Floating Value:  

Control Bus:  

Array Bus:  

 

Helpful Hints: 

● Read direction carefully. Be sure not to skip steps or try to make the 

system in your own way. It will be difficult for the TAs to help you debug 

your code 

● Save often. Labview has some issues that may cause it to crash 

● DO NOT select the drop down from the front panel before saving. There 

is a bug in Labview that will cause it to crash sometimes. If this issue 

occurs, restart your session. If it does crash there is a good chance 

labview saved some of your work! 

 

 

 

 

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