New York City College
of Technology
Department of Electrical and
Telecommunications Engineering
Technology
EET 3120-E260[35142]
Experiment #3
Introduction to NI-ELVIS II Workstation
Student
Professor.
David R. Perez Ramos
Viviana Vladutescu
Team members
Damian Robinson
Shawn Clarke
March 19, 2015
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Contents
Introduction: ................................................................................................................................................. 3
Theoretical Background ................................................................................................................................ 3
Procedure:..................................................................................................................................................... 3
Analysis: ................................................................................................................................................... 4-15
Conclusion: .................................................................................................................................................. 16
References: ................................................................................................................................................. 17
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Introduction:
In this lab we will learn how to use the NI-ELVIS II workstation. The NI-ELVIS II has 12
integrated instruments installed on it such as Oscilloscope, digital multi-meter, function
generator, dynamic signal analyzer. We will practice various experiments which use these
instruments to gain experience with the NI-ELVIS II workstation. We also will combine the NIELVIS II with Lab VIEW to build applications.
Theoretical Background
The voltage divider is a circuit that allows users to divide the input voltage into two parts. Using
Kirchhoff’s second law, the output voltage across the second resistor is given by the formula:
Procedure:
We will do various experiments to put in practice the components mentioned before. These
experiments include the following:
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Measuring component values using NI ELVIS II software
Building a voltage divider circuit on the NI ELVIS II
Measuring current using DMM
Observe voltage development of an RC circuit.
Visualizing the RC transient circuit voltage
Build applications using the NI ELVIS II software and Lab VIEW software
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Analysis:
Measuring component values
In this exercise we will use the NI ELVIS II software to measure resistors values. We first open
the NI ELVIS II software to select the proper tool to measure our capacitors.
Instrument Launcher Icon Strip
Once we have opened our NI ELVIS II software we select the tool that we will to measure our
resistor. The tool used here will be the Digital Multi-meter (DMM).
Digital multi-meter
The DMM provides various functions such as measure volatges, current, resistance and
capacitance. For this exercise we will focus on measure three resistors.
Before we measure the resistors we need to build the circuit in the NI ELVIS II board. The
following image shows our connections and the setup of the components in the NI ELVIS II
board. Using to banana type leads from the DMM on the workstation, we connected to our
resistors and obtained measured values and recorded them. Once we connected our cables to the
resistor we run the DMM application to see the results of the resistor’s measured value. The
resistors measured in this exercise where: 1.0KΩ, 2.2 KΩ, 1.0MΩ.
Resistors
1.0 KΩ
2.2 KΩ
1.0 MΩ
Measured Value
0.983 KΩ
2.14 KΩ
0.978 MΩ
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Supporting image – Measuring resistors values
Building a voltage divider circuit on the NI ELVIS II
Now we will use the NI ELVIS II board to measure voltage. We will build a voltage divider
circuit using the resistors from previous exercise.
Voltage Divider Circuit
Looking at the schematic we build our circuit on the NI ELVIS II board.
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Here, we compared our measure volatge with the calculated volatge .We used the DMM
application to measure the volatge. We also used the resistors measured values from previous
exercise.
Supporting image – Measuring volatge
Parameters
V0
V2 = R2/(R1+R2) *V0
Calculated
5V
3.46V
Measured
4.91V
3.37V
Observing the Voltage Development of an RC
Now, we will measure the capacitance of a 1 µF capacitor and how the voltage transfer through
the capacitor.
RC Transient circuit
Using the 1.0 MΩ and a 1 µF we made the RC transient circuit on the NI ELVIS II board. We
made a few changed in the connection in order to measure the capacitor in the board. We
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connected the capacitor leads to the impedance analyzer inputs, [DUT+] and [DUT-]. Using the
same DMM application we measure the capacitance of the capacitor.
Supporting image – Measuring capacitance on capacitor
When we turned on the board, the voltage across the capacitor rose exponentially. This meaning
that the capacitor start charging with voltages at certain rate of time. The same thing happens
when we turned off the board, the volatge in the capcitor start decreasing exponentionally until it
reaches 0 voltages.
Supporting image – Voltage across capacitor
From this image we can see the digital display %FS linear scale is going up exponentially as we
power up the board. This is when the capacitor is charging with the voltage.
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Visualizing the RC Transient Circuit Voltage
Now, we want to vitualize how the capacitor is charging and discharging in a graph with a
waveform. We can acomplish this by using the Lab VIEW software and the NI ELVIS II board
together. Using the same schematic from before, we made our circuit with the same components.
We changed the voltage source from the +5V supply to the variable power supply on the board.
Connect the output voltage, VC, to the first analog input socket, AI 0[+], and ground the AI 0[-]
socket.
We now open the RC transient.vi program from Lab VIEW software. This program uses
LabVIEW APIs to turn the variable power supply to a set voltage of +5 V for 5 s and then to
reset the VPS voltage to 0 V for 5 s while the voltage across the capacitor is measured and
displayed in real time on a LabVIEW chart.
The Lab VIEW program was already created in our computer, so we just opened and ran it. It
read the connections of our circuit:
Supporting image – Lab VIEW RC Transient. Vi.
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Supporting image - Charging and discharging waveform
From this image we can see when the capcitor is charging and discharging. The volatge increase
and dicrease as the time pass.
Voltage Divider application
We builded a voltage divider circuit using the NI ELVIS II workstation. Here, we first used two
resistors of 5.6 KΩ with an input voltage of 5V and measured the voltage between the resistors
using DMM from the instrument launcher icon strip. Then we changed the R2 value and
measured the voltage again.
Schematic of Voltage divider circuit
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Here is the measured volatge using the DMM the instrument launcher icon strip.
Note: There is a mistake in the reading of the measured voltage. The voltage supposed to be
2.5 V according to Kirchhoff’s second law. We connected our ground in the wrong slot.
We did not connect the groung properly. This make our measured value wrong.
Calculations:
Formula
𝑉2
𝑅2
𝑉𝑐𝑐
V2 with 5.6 KΩ
V2 with 1MΩ
𝑉𝑐𝑐
= 𝑅1+𝑅2 = V2 = 𝑅1+𝑅2 *R2
5𝑉
5𝑉
V2 = 5.6 KΩ+5.6 KΩ *5.6 KΩ = 2.5V V2 = 5.6 KΩ+1MΩ *1MΩ KΩ = 4.9V
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Build a thermometer using the DMM SFP
Now, using the same divider circuit, created a thermometer using a temperature sensor. We
replaced R2 with the LM335 temperature sensor. This sensor senses the temperature around it.
We measured the voltage of the sensor a different levels of temperatures. We first measured the
voltage of the circuit without applying temperature to the sensor. Then we hold the sensor to
increasing the temperature and to record the voltage at that level.
Decreasing voltage when no holding sensor
Increasing voltage when holding sensor
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Building a thermometer using the DMM Express VI Lab VIEW
Now, we used the same circuit and replaced the R2 resistor with a LM335 temperature sensor to
measured temperature in various scales such as Kelvin, Celsius, and Fahrenheit. We used The
Lab VIEW to perform this part. Using the NI ELVISmx from Lab VIEW we can open a DMM
and connect our circuit with it.
Schematic of temperature measurement circuit
We used our temperature subVI from Lab two and applied a few modifications to it. We
eliminated the voltage subVI and placed the NI ELVISmx DMM connected with the temperature
subVI. We also added a scale select to switch between scale temperature (Kelvin, Celsius, and
Fahrenheit).
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Supporting image - Circuit of the thermometer on NI ELVIS II
After all connections are done, we powered up the proto board and ran the
application in Lab VIEW to how the thermometer responded.
Temperature displayed in Celsius.
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Here, we are measuring the temperature in Celsius. When we ran the program the
sensor was detecting the temperature around the environment. We put our hand on
the sensor to increase the temperature and we experienced the temperature on the
sensor getting hot. This was displayed in the graph. First it was low, and then it
started getting high. We repeated this process with the scales in Kelvin and
Fahrenheit too.
Temperature displayed in Kelvin.
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Temperature displayed in Fahrenheit.
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Conclusion:
This lab was very interesting because we learned how this Lab VIEW software and NI ELVIS II
proto-board can create useful application using simple circuits. We gained very good experience
measuring voltage and temperature with useful tools provided by NI ELVIS II and lab VIEW.
Working with the proto board feels like using a lot of integrated instruments installed in one
device. The by NI ELVIS II and lab VIEW not only shows the results of calculations in digital
application, but it also can show the results in graphs which give us a better understanding of the
results we obtain in the Labs.
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References:
Laboratory Manual EET 3120 (Spring 2015) . by Prof. Viviana Vladutescu
"Voltage Divider - Voltage Division Rule - Solved Problems." Solved Problems. N.p., 24 May
2010. Web. 04 May 2015.
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