Electrical and Telecommunications Engineering

Technology Department

EET 3120Sensors And Instruments

Instructor: Viviana Vladutescu

Experiment #3 GROUP #6 Group members : WILFREDO GONZALEZ & MOMODOU NJIE

INTRODUCTION TO NI-ELVIS II WORK STATION

Date of Experiment: 3/12/2015Report Due Date: 3/19/15

MOMODOU NJIE #6671

Table of Contents:

1. Objective – Page 2

2. Brief Theory – Page 2

3. Programs/Results – Page 3-14

4. Conclusion – Page 14

INTRODUCTIONS:

A computer based instrument is assembled inside or outside a computer and uses the

computer for data acquisition, processing measurement, display and communication. A

computer based instrument consists of the following components:

The computer

Hardware for data acquisition and instrument communication.

Computer based instrumentation software.

Objective:This lab introduce the idea of a computer based instruments through building a

simple instrument using the NI ELVIS II workstation and controlling it with a LabVIEW

program. The lab also gives a short tutorial for LabVIEW programming

Equipment:

LabVIEW 2010, NI ELVIS II software, Digital Multimeter, Digital Voltmeter, Digital

Ammeter, Digital Ohmmeter, Digital Capacitance Meter, 1 Kilo-Ohms Resistors, 2.2

Kilo-Ohms Resistors, 1Mega- Ohms Resistors, 5.6 Kilo-Ohms Resistors, 1 Micro-farad

capacitor. We will require also several hardware components to build the circuit which

include Wires to build circuits, 2 Vernier Analog Proto Board Connectors, Vernier and

Lab VIEW NI ELVIS II software application programmatic interface Virtual Instrument.

Theory needed:

LabVIEW is a graphical programming environment that is used by engineers and

scientists in order to develop sophisticated measurement, test, and control systems using

intuitive graphical icons and wires that resemble a flowchart. This program offers strong

integration with thousands of hardware devices and provides a lot of built-in libraries for

advanced analysis and data visualizations. In addition, this program is also scalable

across multiple computer targets and operating systems, becoming an industry leader

since its introduction in 1986. LabVIEW helps their users build measurement

applications in the shortest amount of time and without requiring them to have a

computer science degree

This software also has 12 virtual instruments for hands-on learning, which includes

circuit designing, control designing, digital electronics, microcontroller systems,

telecommunications, and renewable energy.

Procedure of the Experiment :

First and famous we are going to open labview program

Two windows will pop up, block diagram and front panel, then connect the NI ELVIS II

workstation to a computer and power up NI ELVIS II

Input data using controls palette from the view menu.

On the computer screen, click on the NI -ELVISmx instrument Launcher Icon or shortcut

and a strip of NI ELVIS II appears on the screen.

Connect two Banana- type leads to the digital Multimeter input, COM on the left of the

workstation and connect the other end to one end of the resistor.

Then click on the DMM icon within the Launcher strip to select the digital multimeter

and measure the resistance of the resistors.

Results and analyses:

The 1Kilo-Ohms resistor measured 1.0098 Kilo-Ohms

The 2.2 Kilo-Ohms resistor measured 2.1505 Kilo-Ohms

The 1Mega-Ohms resistor measured 0.971 Mega-Ohms

ON the next Exercise we build a Voltage Divider circuit with a 1Kilo-Ohms resistor and

a 2.2 Kilo-Ohms resistor . After making all the necessary connections we then

measured the input Voltage {Vo} with the DMM and obtain 3.3561Vdc.

According the circuit theory V2 R2/(R1+R2)*Vo

By using the previous measurement values above we can calculate V2 by

V2 R2/(R1+R2)*Vo

V2 2.1505k/(1.0098k+2.1505k)*3.3561V

V2 2.2837V

Note that measured value which is 3.3561V is totally different or way higher than the

calculated value which is 2.2837V

On this exercise we used the DMM to measure the current:

Using Ohm’s law we calculated the current by

I V/ R

I 3.3561/2.2

I0.0015A

The measured and calculated values are more or less the same because the calculated

value is 0.0015A and the measure is 0.0009A

On the next exercise we observed the voltage develop on an RC Transient circuit by

replacing both resistors with a 1M resistor and a 1F capacitor. The capacitor is then

measured with the protoboard energized and the measured value was 1.06F

After our circuit is complete on our board, we opened LabView, and opened the RC Transient.vi

VI. This VI shows us the charging and discharging of our RC circuit, as shown in the following

waveform:

Vi. See figure shown below:

With this circuit set-up, we click "run" on the DMM SFP and observe the measured

voltage. We multiplied this voltage by 100 to obtain a temperature in Kelvins. By putting

our hand on the temperature sensor, we may see the temperature change.

Building a thermometer using the DMM express VI in LabView

By starting up LabView, then opening the temperature monitoring.vi, we made the

following modifications: We proceeded to the measurement I/O, then NI ELVISmx and

selected the NI ELVISmx DMM express VI. We placed this into the while loop from the

temperature monitoring.vi, as shown:

With this done, we proceeded to delete the voltage vi already included from the

previous VI, and connected this wire to the DMM. As seen from the picture, we also

created the scale select from right clicking on the scale select input of the temperature

subVI and creating the control. With these steps complete, we ran the VI and observed

the temperatures.

Exercise 2: Building a thermometer using the DMM using the SFP

Measured voltage across LM335 was 2.9955 volts.

So, t [K] =U [V]*100

Dmm SFP

Building a thermometer using the DMM express VI in LabView Temperature values by using LabViewL

DMM SFP Hand Temperature

Start the DMM SFP and press the Run button. Notice the measured voltage. Multiply by

100 manually. The resulting value is temperature in the Kelvin scale. Use Equations to

obtain the temperature in the Celsius and Fahrenheit scales.

. Put your hand on the temperature sensor and notice the modification of the temperature.

Diagram of real Temperature Monitoring

. Navigate to Measurement I/O»NI ELVISmx and select the NI. ELVISmx Digital

Multimeter express VI. Place it inside of the While Loop. The SFP will open (Figure

below).

. Delete the Voltage Read subVI and the connection wire between this subVI and the

temperature subVI.

. Stop the DMM by pressing the Stop button.

. Press the OK button and wait until the compilation of the VI is done.

. Connect the Measurement output of the digital multimeter with the voltage input of the

Temperature subVI (Figure below).

Building a Thermometer Using the DMM Express

Create the Scale select control. Right click on the Scale select input of the Temperature

subVI and select the Create Control option.

. Activate the Panel window of the VI.

. Run the VI and see the measured temperature. Put your hand on the temperature sensor

and notice the variation.

. Select another temperature scale from the Scale select control and see the values.

. Press the STOP button. Save the VI as Real Temperature Monitoring.

Building a Thermometer Using the DMM Express with hand on

CONCLUSION:

In conclusion, we were able to familiarize ourselves with computer based NI ELVIS II and LabView to control the work station. We worked through each exercise which obtained different objectives and measurements, as well as circuit analysis. The last one was challenging but we was able to get results.

References:

Lab manual