What is LabVIEW - G
LabVIEW - DAQ
Data Acquisition
Dr. M. Kostic
NIU - Mechanical Engineering
l Virtual
Instrument Engineering Workbench
l Full-featured Graphical Programming Software
l Designed for Instrumentation and Data
Acquisition
LabVIEW/DAQ by Dr. M. Kostic
LabVIEW/DAQ by Dr. M. Kostic
Virtual Instruments (VIs
(VIs))
What is Virtual InstrumentInstrument-VI
A software designed program to simulate an
instrument (Virtual Instrument)
l Versatile as our creativity
l It is stored in a file any_name.vi extension
l It could be used as a subroutine or main
program
• Front Panel
– Controls = Inputs
– Indicators = Outputs
l
Input
Output
• Block Diagram
– Accompanying
"program" for front
panel
– Components "wired"
together
LabVIEW/DAQ by Dr. M. Kostic
(sub) VI as an Icon
Creating the Icon/Subroutine
Icon
• Pop up in the icon pane
LabVIEW/DAQ by Dr. M. Kostic
Let’
Let’s switch to LabVIEW
software and play....
play....
Show some Examples...
Examples...
• It is recommended to create black and white icon
LV Basics 1 2
Mar 94
LabVIEW/DAQ by Dr. M. Kostic
LabVIEW/DAQ by Dr. M. Kostic
Lab VIEW Summary
l Virtual Instruments (VIs
(VIs))
v Front Panel v Block Diagram v Connector/Icon
DAQ
l Two windows to create a VI
v Panel window (I/O) v Diagram window (Program)
l PullPull-down menus
v Controls menu to place controls/indicators (I/O) in Panel
window
v Functions menu to place program nodes in Diagram
window
or
Data Acquisition
l All LabVIEW objects have poppop-up menus
l Nonexecutable VIs indicated by...
LabVIEW/DAQ by Dr. M. Kostic
LabVIEW/DAQ by Dr. M. Kostic
Data Acquisition - DAQ
DAQ Scope
l About plugplug-in data acquisition (DAQ) boards.
l About the organization of the DAQ
DAQ boards:
FCOMPUTER
Analog
I/O BOARD:
SIGNAL
CONDITIONING:
Modify
transducer
with SOFTWARE:
Control
the DAQ signals
board,
PLUG-IN
DAQ
Measures
(acquires),
PLUG
TRANSDUCERS:
Sense
the
measured
quantities
FDigital
I/Ostore,
to
match
DAQ
board
specs/ranges.
Examples:byamplification
process,
and
display
data,as
asinstructed
instructed
software
processes,
stores,
and
generates
signals,
and change
their
properties
or
generate
corresponding
FCounter/timer I/O
or Examples:
attenuation,
filtering,
excitation,
etc. to acquire
program.
Examples:
LabVIEW
application
programs
by software
program.
and
digital
electrical
signals.
Examples:
strainAnalog
gage,
thermocouple,
n DAQ library supports all DAQ boards
data, and
simulate
instruments,
and
signals’accelerometer,
input
output,
counters, timers,
etc. results, etc.
potentiometer,
etc.-generate
n LabVIEW uses the NIlevel software
NI-DAQ driverdriver
n
VIs.
VIs.
l How to acquire and display an analog signal.
Data Acquisition System Components
l How to perform a timed data acquisition.
l How to acquire data from multiple analog
channels.
l How to drive the digital I/O lines, and the
basics of buffered data acquisition.
LabVIEW/DAQ by Dr. M. Kostic
LabVIEW/DAQ by Dr. M. Kostic
Transducers
Signal Conditioning
Sense Phenomena
Produce Electrical Signal
Condition Transducer Signals
Make Signal Suitable for DAQ Board
Examples:
Examples:
l
l
l
l
l
Thermocouples, Thermistors
Strain Gauges, RTDs
Pressure Transducers, Load Cells
Accellerometers,
Accellerometers, Microphones
Potentiometers, Etc..
LabVIEW/DAQ by Dr. M. Kostic
l
l
l
l
l
Amplification/Attenuation
Linearization/Calibration
Filtering
Multiplexing (up to 3,072 channels)
Isolation, Excitations, Etc.
LabVIEW/DAQ by Dr. M. Kostic
DAQ Hardware & Software
Typical DAQ Board
Configurations
Main Features:
F
F
F
F
Hardware:
Analog I/O (Input/Output)
Digital I/O
Timer/Counter I/O, Triggering
Accuracy, Flexibility, Reliability, Expandability
F
F
F
Typical Specifications:
F
F
F
F
F
F
Computer Platform:
Input Channels:
Max. Sampling Rate:
Resolution:
Gains:
Range:
(E)ISA, PCMCIA, PCI, NuBus
8-16 SEnd, 4-8 DIff
50-500 (1,250) kHz
8-16 bits
1,2,5,10,20,50,100 Times
( ± 2.5) ±5, (0-5) 0-10 Volt
Setting DIP Switches and Jumpers for Particular
Options/Applications
Newer and Plug-and-Play Boards are Software
Configured
Cabling, Signal Conditioning, Terminal Blocks, etc.
Software:
F
F
F
Set-up and Configuration Programs
Drivers: Interface between DAQ Board and Computer
DAQ Application Software (LabVIEW, C, Basic, etc.)
K
K
K
LabVIEW/DAQ by Dr. M. Kostic
Data Acquisition
Data Analysis (Statistics, FFT, DSP, etc.)
Data Presentation (Graphing, Plotting, Tabulation, etc.)
LabVIEW/DAQ by Dr. M. Kostic
Analog Input Considerations
DAQ Software Architecture – Windows
• SingleSingle-Ended vs. Differential
8
10 V range
WDAQCONF.EXE
• Resolution
10
• Range
1* 212
LabVIEW for Windows
20
.
= 2.4. mV
1* 212
1X Gain
= 4.8 mV
DAQ Library VIs
12 bit
resolution
• Sampling Rate / Aliasing
Time
DAQDRV
NI-DAQ for Windows
DLL
Aliasing
Adequately sampled
WDAQCONF.EXE
Aliased due to undersampling
• Averaging / Noise reduction
3-bit ADC
16-bit ADC
LabVIEW/DAQ by Dr. M. Kostic
Analog Input and Output VIs
AI Sample Channel
AO Update Channel
LabVIEW/DAQ by Dr. M. Kostic
Now, new operating systems
and application software versions
make CONFIGURATION ESEAR!
DAQ Board
LabVIEW/DAQ by Dr. M. Kostic
Waveform Input and Output VIs
AI Acquire Waveform
AO Generate Waveform
LabVIEW/DAQ by Dr. M. Kostic
Digital Input and Output
DAQ Summary
l Identify I/O Signal Types:
Write to Digital Line
Read from Digital Line
Write to Digital Port
Read from Digital Port
Transducers/Controllers
l Choose a Signal Conditioning Method
l Select a Data Acquisition (DAQ) Device
l Choose Terminals/Cables for the Hardware
l Select DAQ Software
LabVIEW/DAQ by Dr. M. Kostic
LabVIEW/DAQ by Dr. M. Kostic
The Art of
Signal Sampling and Aliasing:
W.W.S.N.W.I.I.
"
What We See is Not What It Is!"
Simulation with a LabVIEW Virtual Instrument
™
"What
We See is Not What It Is!"
Prof. M. Kostic
Mechanical Engineering
⇒It’
It’s all about ...
… Sampling and Aliasing!
⇒Even ...W.Y.S.W.Y.G.
...W.Y.S.W.Y.G.
"What You See is What You Get!”
⇒…is REALLY NOT true (the same)
on different Monitors and Printers
NORTHERN ILLINOIS UNIVERSITY
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
Signal//Magnitude Resolution
Signal
Signal/Sampling Resolution
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
There is NO
such thing as...
⇒…too large hard drive disk, or ...
⇒…too large sampling resolution!
resolution!
Sampling/
Sampling/Time Resolution (Speed)
Speed)
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
⇒Well praised ...
highhigh-definition digital graphics
and CDCD-quality music
⇒…are NOT good (true) enough!
enough!
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
(Under)
Under)Sampling & Aliasing ...
Real measurements
of a simple sinesine-harmonic
• UnderUnder-sampling looses
(important) wave details !
• But it also may change the wave
form/shape due to Aliasing !
© MCMXCIX* Prof. M. Kostic
www.kostic.niu.edu
How come this if the measured signal
is a simple sine-harmonic wave?
Real signal
Real signal
Samp
led sig
nal
Samp
led sig
nal
© MCMXCIX* Prof. M. Kostic
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
www.kostic.niu.edu
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
Sampling RPM with Stroboscope
If RPM and Strobe speeds
(frequencies) are the same
the reference mark will
appear stationary
(ZERO aliasing)
Real signal
Samp
led sig
nal
t
e ligh
oscop
b
o
r
t
S
If the Strobe speed is faster
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
www.kostic.niu.edu
If the Strobe speeds is
half of RPM, the disk will
turn twice and the mark
will appear stationary again!
Rotating disk
(RPM)
If the Strobe speed is slower
© MCMXCIX* Prof. M. Kostic
Interactive Experiments ...
LabVIEW Virtual Instruments
Internet Interactive Experiment
Animated Movie
NO
Alias.
ZERO
Aliasing
www.kostic.niu.edu
Aliasi
ng
© MCMXCIX* Prof. M. Kostic
Who does the future belongs to ?
© MCMXCIX* Prof. M. Kostic
www.kostic.niu.edu
No Limits …
NO
The Future
Belongs
To…
To…
www.kostic.niu.edu
© MCMXCIX* Prof. M. Kostic
Instrumentation with
Computerized Data
Acquisition for an Innovative
Thermal Conductivity Apparatus
Prof. M. Kostic
Mechanical Engineering
NORTHERN ILLINOIS UNIVERSITY
SPEED
LIMIT
www.kostic.niu.edu
… Whoever
Gets There
First
© MCMXCIX* Prof. M. Kostic
Introduction
Which teaching/learning method is better…
better…
theoretical vs. experimental,
...traditional vs. newnew-tech aided,
...inductive vs. deductive…
deductive…?
It’
It’s like…
like…which coldcold-medicine is the best…
best…
… “chicken or egg, which one came first”…
?
first”…?
There is NO the best…
best…
…”rightright-mixture”
mixture” of all…
all…is the best!
best!
Introduction (Cont’
(Cont’d)
This research application...
...looks
...looks complex for undergraduates
But, simple and “inin-principle”
principle” examples
...are not enough for good professional
training
Goal...
...To work inin-depth a “nice”
nice” complex
application
Objectives
In addition to basics instrumentation,
measurements...
...show students a purposeful, complex
application
…which was a real professional funded
project, and
…which employs Computerized (“
(“OnOn-Line”
Line”)
Data Acquisition
Engineering challenge:
challenge:
What is to be accomplished ?
• An innovative method and a novel research
apparatus
• to measure the thermal conductivity of a
nonnon-Newtonian fluid while it is subjected to
shearing flow,
flow, and
• to determine its dependence, if any, on
shearing itself.
Introduction (Cont’
(Cont’d)
Computerized data acquisition hardware and
LabVIEW development and application
software
...in
...in engineering curriculum at NIU
...starting with Experimental Methods I and II
ME courses
Objectives (Cont’
(Cont’d)
To demonstrate, analyze and discuss:
• Engineering challenge -What is to be
accomplished?
• Mechanical and Electrical Design
• Instrumentation and Measurements
• Computerization and Data Acquisition
Engineering challenge (Cont’
(Cont’d)
This is contrary to the current statestate-ofof-thethe-art
of measuring thermal conductivity under the
condition of motionless fluid,
...to avoid convective heat transfer influence on
the results.
Mechanical and Electrical Design
Mechanical and Electrical Design
TC Apparatus
(Cont’
(Cont’d)
The main testtest-section
dimensions:
Main and Guard Heaters
• D/d=2.598/
D/d=2.598/ 2.488 in
outer/inner cylinder
diameters respectively
• with the 0.055 in
Outer Cylinder
thick gap,
gap, filled with
the testtest-fluid ininbetween
Instrumentation
and Measurements
1
16 Thermocouples
2
DC voltage drop (across
Instrumentation
and Measurements
3
(Cont’
(Cont’d)
1
1• AT-MIO-16DE-10 data
acquisition board
the main heater and a
precise current resistor for
power meas.)
meas.)
3 Set & control guard
heating (Solid(Solid-state
multiplexer-signal
conditioning module for
thermocouples
3
4• SCXI-1322 shielded terminal
block (w/ CJC)
5• SCXI-1353 shielded cable
4
assembly
(motor drive and
6j Two CB-50 terminal blocks
tachometertachometer-sensor)
ATAT-MIOMIO-16DE16DE-10
Data Acquisition Board
with NB-1 extensions
Computerization and
Data Acquisition
•
feed-back control for DC motor-drive
using a calibrated tachometer-sensor
• Up to 100 kSamples/sec
• 16 singlesingle-ended/8 differential channels,
•
solid-state relays for efficient and
accurate feed-back control of guardheaters’ power
•
• two 1212-bit analog outputs
• 32 digital I/O channels
• two 2424-bit, 20 MHz counter/timers
comprehensive over-heating
protection
•
interactive and comprehensive
monitoring for the kinematics and
thermal steadiness of all processes
and
•
convenience of increasing the number of
thermocouple sensors for more
advanced measurements
E Series architecture
1212-bit analog inputs
2
4
6
conditioning chassis
3• SCXI-1122 16-channel
Set & control cylinder
rotational speed
Inner Cylinder
2• SCXI-1000 4-slot signal
2
Relays)
4
Bearing with
Dynamic Seal
1
3
5
Computerization and Data Acquisition (Cont’
(Cont’d)
Conclusion
• One of the objectives
...to utilize the latest powerful, yet
inexpensive, technological developments:
sensors and transducers,
• data acquisition and control integrated
boards,
• computers and application software,
...for research and teaching by
example.
Conclusion (Cont’
(Cont’d)
The designed, computerized measurement and
data acquisition system, accomplishes the
following objectives:
•
•
•
•
acquire measured data with high speed and accuracy
interactively process and analyze measured data for
immediate use or future postpost-processing
provide interactive and accurate feedfeed-back process
control - motor speed and guardguard-heating power, and
Conclusion (Cont’
(Cont’d)
In addition this system allows for...
easy modification and enhancement
of so called
“virtual (software) instruments”
instruments”
...by modification of software programs.
interactively displays the raw/measured and
processed/analyzed data in graphical and/or numerical forms
Conclusion (Cont’
(Cont’d)
Conclusion (Cont’
(Cont’d)
• Will NewTech replace/endanger traditional
• NewNew-Technology
Technology developments
values, humans? - Definitely NOT!
Should we use NewTech to our benefits Definitely YES!
• Remember, the TV has never endangered
Printed Press; the both have been
enhancing each other!
• We do not have to change, but we have to
adopt to changes (NewTech including)!
...maturity, critical mass, wide use
provide for new ways to improve
engineering curriculum and
enhance learning environment
• Either lack of use, or abuse of modern
technological and computational tools
• NewTech should be our Slave, NOT our Master.
Conclusion (Cont’
(Cont’d)
"Location, Location, and Location!"
…as Realtors said.
"Access, Access, and Access!",
…as Internet nerds said.
"Time, Time, and Time!",
…as Businessmen said.
"Quality, Quality, and Quality!”
Quality!”
…as it really matters.
You may contact Prof. Kostic at:
mailto: kostic@niu.edu
or on the Web:
http://www.kostic.niu.edu
http://www.kostic.niu.edu
Acknowledgment
• National Science Foundation support (Grant No.
CTSCTS-9523519).
• Graduate School of Northern Illinois University
(NIU)
• Department of Mechanical Engineering
• Mr. Haibo Tong, graduate student and
Mr. Al Metzger, for mechanical design and
fabrication
• Mr. Bill Vickers, for electronics design and
fabrication