LabVIEW lecture handout by Prof. d k chaturvedi

Prof. D.K. Chaturvedi
Dept. of Electrical Engineering
D.E.I. (Deemed University)
Dayalbagh, Agra

LabVIEW
LabVIEW-Laboratory Virtual Instrument Engineering Workbench
 LabVIEW programs are called Virtual Instruments(VIs) as they imitate physical instruments.
 Graphical Programming language.
 We can build user interface called front panel with controls and indicators.
ADVANTAGE
 Higher Modular code
 User friendly interface
 Easy to use development environment
 Provides the capability to build instruments
as per our requirements.
 No obsolescence
 Cost effective instruments.
Front Panel
(User Interface)
Block diagram
(Programming Window)

Suppose we are interested to measure the following parameters of a
periodic signal
RMS value of the voltage
Average value
Frequency
True shape of the waveform
To measure the above parameters, we need the following equipments:
 Function generator
 AC voltmeter
 Frequency meter
 Phase angle
 CRO
We will prefer to measure the above parameters by a single
instrument

Generating a periodic signal and measuring parameters of the
signal by labview

Labview is a graphical programming system designed for data acquisition,
data analysis, and instrument control
LabVIEW program can run on PC Windows, Macintosh and VXI systems, and
is transportable from one system to another.
LabVIEW uses graphical symbols (icons) to describe programming actions
while other language use text for instruction code
LabVIEW programs are called virtual instruments (VIs) because its
appearance and operation imitate actual instruments
When started, two windows are open: (i) Front panel, it simulates front panel
of physical instruments (ii) the Block diagram shows the internal components of
the program
Front panel can contain control knobs, push button, graph, indicators and other
controls
The control and indicator are connected to other operators and program blocks
Each program block has different symbol and data type has different colour
What is Labview

When we start LabVIEW, we will see a screen with a few options on it.
o This is front panel.
o Here we can input data and view results
o Data can also be inputed through data
file or DAQ cards
Right click the cursor on front panel
o There are numeric, Boolean, string, array, graph, and
other controls VI.
o Select numeric control VI and place it on front panel
o Select another numeric VI to display measured value
Numeric
control
Numeric
display

Block diagram window will be used to create VI programs
Program can be made using Inputs and
Outputs of Front panel and Objects from
Function window
Labview allows user to set breakpoint and examine data
inside the program
Click on red dot on tool manu and then set breakpoint
on add icon
Click run button on block diagram window and select
probe tool from tool menu
Click three probes on data path. Three windows will
open with values on each path.
Click run button to see x+y.

Labview program to display square of numbers
 Open new VI (front panel and block diagram)
 Select digital numeric control and waveform graph in front panel
 Now select block diagram window and open function window
 Select FOR loop (under structure menu) , multiply VI(under numeric
menu), Build array (under Array menu) and Write to spread sheet block
(under file I/O menu)
 Connect ‘N’ of FOR loop to numeric control menu, ‘i’ to inputs of
multiplier, Output of multiplier to input of build array menu, Output of
array to Graph VI and Spread sheet VI.
 i = 0, 1, 2…… N (Input of digital control), output of multiplier = i*i.

Modeling of Temperature sensor using Labview VI blocks
 The characteristics equation of a NTC given thermistor
RT = R0 exp(β/T- β/T0),
RT resistance at any Temp T °K, R0 resiatnce at ° K, β characteristics coefficient
(3500-4000°K), the equation can be further written as
ln (RT/R0) = [ β/T – β/T0] and
T = β/[ln (RT/R0 + β/T0]). If we know β, R0 and RT at any temperature T,
then it can be used to display temperature directly.
Following components are required to model thermistor using VI
- Sensor data simulator.
- Voltage to thermistor resistance converter module.
- Calibration & presentation module
Warning system
- Password protection (if we are interested)

Sensor Data Simulator Module
Temperature range: 00C to 650C
Corresponding voltage range (Signal Conditioning
Circuit Output): 0.45 V to 1.45 V
This voltage range is generated using random
number generator VI in numeric menu of Labview
Here 10 random numbers are averaged to get
average Vo
To obtain actual Thermistor Resistance RT at
temperature T from voltage output the
following equation is implemented
RT =((Vi – V0) / V0 ) * Rs
Where RT– Thermistor Resistance at T
Vi – Input voltage (= 5 V)
Rs – Series resistance (= 1 K-ohm)
V0 – Voltage across Rs

Conversion of Vo to RT using Labview
RT =((Vi – V0) / V0 ) * Rs
Front panel for RT

Calibration And Presentation Module
The calibration module implements following expression:-
T = /[{ln(RT/ R0)}+ /T0] --------
RT Thermistor resistance at T (K)
T Thermistor temperature (K)
R0 Resistance at T0 (K)
 Thermistor characteristics constant (K)

Integrated Block Diagram to simulate inverse model of
thermistor

Front Panel Of The Developed Application

The Alarm Module
Alarm module in the designed application is used to check the variation of
measurand beyond and below certain user specified boundaries. The
application will work if the parameter is within range, otherwise it will give
the range violation alarm. The design is sensitive to temperature range
between 60C and 30C.

Online Temperature Measurement Using Labview
Vi
RTH
R=1Kohm
DAQ
Device
LabVIE
W
Vo
+
-
Real Time
Data File
National Instruments
DAQ card

Real-time humidity and temperature measurement using Labview

Front panel of the application

LabVIEW APPLICATION
SYSTEMS where LabVIEW is being used
during performance evaluation trials
• Parachute systems
• Aircraft Arrester barrier System(AABS)
• Heavy Drop System(HDS)
• Controlled Aerial Delivery System(CADS)
• Floatation systems for Space recovery module
• Human Space Program(HSP) deceleration system
etc.
For performance evaluation of the various systems developed in ADRDE,
Instrumented trials are conducted using Telemetry and Data Acquisition Systems.
LabVIEW is used as Data Acquisition and Data Analysis Tool.
Measured Parameters
Snatch and Opening Shock of
Parachute
 Steady load and terminal
velocity of parachute systems.
Burst pressure measurement of
Floats
Impact measurement
Oscillation of payload
Load Profile Acc/Dec Profile OscillationAltitude Profile Rate of Descent

TELEMETRY AND DATA ACQUISITION
TELEMETRY
Data Acquired from various sensors are transmitted through
wireless channel. At Ground Station, these signals are received,
acquired and processed using Data acquisition card and PC with
LabVIEW VI.
Receiver Discriminator
DAQ
Card
Antenna
PC with
LabVIEW

ONBOARD DATA ACQUISITION
Data from various sensors is recorded using microcontroller
based Data Acquisition system. Data is stored in the internal
memory of the DAQ system.
Stored data is then downloaded to PC using HyperTerminal for
post trial Analysis using LabVIEW application.
SENSOR
MICRO CONTROLLER BASED
DATA ACQUISITION SYSTEM
WITH STORAGE MEMORY
Data Acquisition
MICRO CONTROLLER BASED
DATA ACQUISITION SYSTEM
WITH STORAGE MEMORY
PC with
HyperTerminal
Data Downloading

ONLINE DATA ACQUISITION SYSTEM
Used when parameters to be recorded are easily accessible. Sensors output is directly acquired by PC using
DAQ card and LabVIEW VI
Sensor DAQ Card
PC with
LabVIEW
Sensor output is acquired and recorded
using LabVIEW
Recorded data after data analysis
Impact Measurement using LabVIEW

DATA ANALYSIS USING LabVIEW
Data recorded using DAQ system Data analysis using LabVIEW: Load profile
Data analysis using LabVIEW: Acceleration Profile Data analysis using LabVIEW: Altitude Profile

DEVELOPMENT OF DISCRIMINATOR
Discriminator hardware has been replaced by LabVIEW application
ADRDE has a patent for the scheme.
STRAIN MEASUREMENT SYSTEM-PXI BASED DATA ACQUISITION SYSTEM
Four SCXI-1520 modules capable to interface
32 strain gauge bridges and other Wheatstone
bridge based sensors.
 Used for strain measurement on metallic
structure.
NIcRIO Data Logger
 Modular Telemetry and data Acquisition system
 Video Acquisition using LabVISION.
 Real time application.
Receiver Discriminator DAQ Card
Antenna
PC with
LabVIEW

LabVIEW lecture handout by Prof. d k chaturvedi

More Related Content

What's hot (18)

Similar to LabVIEW lecture handout by Prof. d k chaturvedi (20)

Recently uploaded (20)

LabVIEW lecture handout by Prof. d k chaturvedi