LabVIEW - DAQ Data Acquisition. Dr. M. Kostic. NIU - Mechanical Engineering. What is LabVIEW - G. V irtual I nstrument E ngineering W orkbench Full-featured Graphical Programming Software Designed for Instrumentation and Data Acquisition. Watch NI Demo. What is Virtual Instrument-VI.
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Dr. M. Kostic
NIU - Mechanical Engineering
Watch NI Demo
Virtual Instruments (VIs)
Front Panel Block Diagram Connector/Icon
Panel window (I/O)Diagram window (Program)
Controls menu to place controls/indicators (I/O) in Panel window
Functions menu to place program nodes in Diagram window
COMPUTER with SOFTWARE: Control the DAQ board,
process, store, and display data, as instructed by software
program.Examples: LabVIEW application programs to acquire
data, simulate instruments, and generate results, etc.
SIGNAL CONDITIONING: Modify transducer signals
to match DAQ board specs/ranges.Examples: amplification
or attenuation, filtering, excitation, etc.
PLUG-IN DAQ BOARD: Measures (acquires),
processes, stores, and generates signals, as instructed
by software program.Examples: Analog and digital
signals’ input and output, counters, timers, etc.
TRANSDUCERS: Sense the measured quantities
and change their properties or generate corresponding
electrical signals.Examples: strain gage, thermocouple,
accelerometer, potentiometer, etc.
Produce Electrical Signal
Condition Transducer Signals
Make Signal Suitable for DAQ Board
• Single-Ended vs. Differential
• Sampling Rate / Aliasing
• Averaging / Noise reduction
10 V range
Aliased due to undersampling
LabVIEW for Windows
DAQ Library VIs
NI-DAQ for Windows DLL
Now, new operating systems
and application software versions
make CONFIGURATION ESEAR!
AI Acquire Waveform
NORTHERN ILLINOIS UNIVERSITYThe Art of Signal Sampling and Aliasing:Simulation with a LabVIEW™ Virtual Instrument
"What We See is Not What It Is!"
Sampling/Time Resolution (Speed)
How come this if the measured signal
is a simple sine-harmonic wave?
(frequencies) are the same
the reference mark will
If the Strobe speeds is
half of RPM, the disk will
turn twice and the mark
will appear stationary again!
If the Strobe speed is slower
If the Strobe speed is fasterSampling RPM with Stroboscope
LabVIEW Virtual Instruments
Internet Interactive Experiment
NORTHERN ILLINOIS UNIVERSITY
Instrumentation with Computerized Data Acquisitionfor an Innovative Thermal Conductivity Apparatus
Which teaching/learning method is better…theoretical vs. experimental,...traditional vs. new-tech aided, ...inductive vs. deductive…?
It’s like…which cold-medicine is the best…… “chicken or egg, which one came first”…?
There is NO the best……”right-mixture” of all…is the best!
This research application... ...looks complex for undergraduates
But, simple and “in-principle” examples...are not enough for good professional training
Goal......To work in-depth a “nice” complex application
Computerized data acquisition hardware and LabVIEW development and application software ...in engineering curriculum at NIU ...starting with Experimental Methods I and II ME courses
In addition to basics instrumentation, measurements...
...show students a purposeful, complex application
…which was a real professional funded project, and
…which employs Computerized (“On-Line”) Data Acquisition
To demonstrate, analyze and discuss:
This is contrary to the current state-of-the-art of measuring thermal conductivity under the condition of motionless fluid,...to avoid convective heat transfer influence on the results.
The main test-section dimensions:
Main and Guard Heaters
...for research and teaching by example.
The designed, computerized measurement and data acquisition system, accomplishes the following objectives:
In addition this system allows for...
easy modification and enhancementof so called “virtual (software) instruments”...by modification of software programs.
"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!”…as it really matters.
or on the Web: