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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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labview daq data acquisition

LabVIEW - DAQ Data Acquisition

Dr. M. Kostic

NIU - Mechanical Engineering

what is labview g
What is LabVIEW - G
  • Virtual InstrumentEngineering Workbench
  • Full-featured Graphical Programming Software
  • Designed for Instrumentation and Data Acquisition

Watch NI Demo

what is virtual instrument vi
What is Virtual Instrument-VI
  • A software designed program to simulate an instrument (Virtual Instrument)
  • Versatile as our creativity
  • It is stored in a file extension
  • It could be used as a subroutine or main program



Virtual Instruments (VIs)

  • Front Panel
  • – Controls = Inputs
  • – Indicators = Outputs
  • BlockDiagram
  • Accompanying "program" for front panel
  • Components "wired" together
lab view summary
Lab VIEW Summary
  • Virtual Instruments (VIs)

Front Panel Block Diagram Connector/Icon

  • Two windows to create a VI

Panel window (I/O)Diagram window (Program)

  • Pull-down menus

Controls menu to place controls/indicators (I/O) in Panel window

Functions menu to place program nodes in Diagram window

  • All LabVIEW objects have pop-up menus
  • Nonexecutable VIs indicated by...



Data Acquisition


DAQ Scope

  • About plug-in data acquisition (DAQ) boards.
  • About the organization of the DAQ VIs.
  • How to acquire and display an analog signal.
  • How to perform a timed data acquisition.
  • How to acquire data from multiple analog channels.
  • How to drive the digital I/O lines, and the basics of buffered data acquisition.
data acquisition daq
Data Acquisition - DAQ
  • DAQ boards:
    • Analog I/O
    • Digital I/O
    • Counter/timer I/O
  • DAQ library supports all DAQ boards
  • LabVIEW uses the NI-DAQ driver-level software
  • Data Acquisition System Components

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.


Sense Phenomena

Produce Electrical Signal


  • Thermocouples, Thermistors
  • Strain Gauges, RTDs
  • Pressure Transducers, Load Cells
  • Accellerometers, Microphones
  • Potentiometers, Etc..
signal conditioning
Signal Conditioning

Condition Transducer Signals

Make Signal Suitable for DAQ Board


  • Amplification/Attenuation
  • Linearization/Calibration
  • Filtering
  • Multiplexing (up to 3,072 channels)
  • Isolation, Excitations, Etc.
typical daq board
Typical DAQ Board

Main Features:

  • Analog I/O (Input/Output)
  • Digital I/O
  • Timer/Counter I/O, Triggering
  • Accuracy, Flexibility, Reliability, Expandability

Typical Specifications:

  • Computer Platform: (E)ISA, PCMCIA, PCI, NuBus
  • Input Channels: 8-16 SEnd, 4-8 DIff
  • Max. Sampling Rate: 50-500 (1,250) kHz
  • Resolution: 8-16 bits
  • Gains: 1,2,5,10,20,50,100 Times
  • Range: 2.5) 5, (0-5)0-10 Volt
daq hardware software configurations
DAQ Hardware & SoftwareConfigurations


  • Setting DIP Switches and Jumpers for Particular Options/Applications
  • Newer and Plug-and-Play Boards are Software Configured
  • Cabling, Signal Conditioning, Terminal Blocks, etc.


  • Set-up and Configuration Programs
  • Drivers: Interface between DAQ Board and Computer
  • DAQ Application Software (LabVIEW, C, Basic, etc.)
    • Data Acquisition
    • Data Analysis (Statistics, FFT, DSP, etc.)
    • Data Presentation(Graphing, Plotting, Tabulation, etc.)
analog input considerations
Analog Input Considerations

• Single-Ended vs. Differential

• Resolution

• Range

• Sampling Rate / Aliasing

• Averaging / Noise reduction


10 V range



1X Gain

12 bit




Adequately sampled

Aliased due to undersampling

16-bit ADC

3-bit ADC

daq software architecture windows
DAQ Software Architecture – Windows

LabVIEW for Windows


DAQ Library VIs


NI-DAQ for Windows DLL


DAQ Board

Now, new operating systems

and application software versions


waveform input and output vis
Waveform Input and Output VIs

AI Acquire Waveform


digital input and output


Write to Digital Line



Digital Input and Output
daq summary
DAQ Summary
  • Identify I/O Signal Types: Transducers/Controllers
  • Choose a Signal Conditioning Method
  • Select a Data Acquisition (DAQ) Device
  • Choose Terminals/Cables for the Hardware
  • Select DAQ Software
the art of signal sampling and aliasing simulation with a labview virtual instrument

Prof. M. Kostic

Mechanical Engineering


The Art of Signal Sampling and Aliasing:Simulation with a LabVIEW™ Virtual Instrument

"What We See is Not What It Is!"

w w s n w i i what we see is not what it is
W.W.S.N.W.I.I."What We See is Not What It Is!"
  • It’s all about ...… Sampling and Aliasing!
  • Even ...W.Y.S.W.Y.G."What You See is What You Get!”
  • …is REALLY NOT true (the same)on different Monitors and Printers
signal sampling resolution
Signal/Sampling Resolution

Signal/Magnitude Resolution

Sampling/Time Resolution (Speed)

there is no such thing as
There is NOsuch thing as...
  • …too large hard drive disk, or ...
  • …too large sampling resolution!
  • Well praised ... high-definition digital graphicsand CD-quality music
  • …are NOT good (true) enough!
under sampling aliasing
(Under)Sampling & Aliasing ...
  • Under-sampling looses (important) wave details!
  • But it also may change the wave form/shape due to Aliasing !
real measurements of a simple sine harmonic
Real measurements of a simple sine-harmonic

How come this if the measured signal

is a simple sine-harmonic wave?


Real signal

Sampled signal


Real signal

Sampled signal


Real signal

Sampled signal

sampling rpm with stroboscope

If RPM and Strobe speeds

(frequencies) are the same

the reference mark will

appear stationary

(ZERO aliasing)

If the Strobe speeds is

half of RPM, the disk will

turn twice and the mark

will appear stationary again!

Rotating disk


Stroboscope light

If the Strobe speed is slower

If the Strobe speed is faster

Sampling RPM with Stroboscope






interactive experiments
Interactive Experiments ...

LabVIEW Virtual Instruments

Internet Interactive Experiment

Animated Movie

no limits




No Limits …

The Future Belongs To…

… Whoever Gets There First


Prof. M. Kostic

Mechanical Engineering


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!

introduction cont d
Introduction (Cont’d)

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

introduction cont d1
Introduction (Cont’d)

Computerized data acquisition hardware and LabVIEW development and application software engineering curriculum at NIU ...starting with Experimental Methods I and II ME courses


In addition to basics instrumentation, measurements... students a purposeful, complex application

…which was a real professional funded project, and

…which employs Computerized (“On-Line”) Data Acquisition

objectives cont d
Objectives (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 what is to be accomplished
Engineering challenge:What is to be accomplished ?
  • An innovative method and a novel research apparatus
  • to measure the thermal conductivity of a non-Newtonian fluid while it is subjected to shearing flow, and
  • to determine its dependence, if any, on shearing itself.
engineering challenge cont d
Engineering challenge (Cont’d)

This is contrary to the current state-of-the-art of measuring thermal conductivity under the condition of motionless fluid, avoid convective heat transfer influence on the results.

mechanical and electrical design tc apparatus
Mechanical and Electrical DesignTC Apparatus

The main test-section dimensions:

  • D/d=2.598/ 2.488 in outer/inner cylinder diameters respectively
  • with the 0.055 inthick gap, filled with the test-fluid in-between
mechanical and electrical design cont d
Mechanical and Electrical Design (Cont’d)

Main and Guard Heaters

Outer Cylinder

Bearing with

Dynamic Seal

Inner Cylinder

instrumentation and measurements
Instrumentation and Measurements






  • 16 Thermocouples
  • DC voltage drop(across the main heater and a precise current resistor for power meas.)
  • Set & control guard heating(Solid-state Relays)
  • Set & control cylinder rotational speed(motor drive and tachometer-sensor)





instrumentation and measurements cont d
Instrumentation and Measurements(Cont’d)








  • AT-MIO-16DE-10 data acquisition board
  • SCXI-1000 4-slot signal conditioning chassis
  • SCXI-1122 16-channel multiplexer-signal conditioning module for thermocouples
  • SCXI-1322 shielded terminal block (w/ CJC)
  • SCXI-1353 shielded cable assembly
  • Two CB-50 terminal blocks with NB-1 extensions







at mio 16de 10 data acquisition board e series architecture
AT-MIO-16DE-10Data Acquisition BoardE Series architecture
  • Up to 100 kSamples/sec
  • 16 single-ended/8 differential channels, 12-bit analog inputs
  • two 12-bit analog outputs
  • 32 digital I/O channels
  • two 24-bit, 20 MHz counter/timers
computerization and data acquisition
Computerization and Data Acquisition
  • feed-back control for DC motor-drive using a calibrated tachometer-sensor
  • solid-state relays for efficient and accurate feed-back control of guard-heaters’ power
  • 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
  • One of the 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 d
Conclusion (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 post-processing
  • provide interactive and accurate feed-back process control - motor speed and guard-heating power, and
  • interactively displays the raw/measured and processed/analyzed data in graphical and/or numerical forms
conclusion cont d1
Conclusion (Cont’d)

In addition this system allows for...

easy modification and enhancementof so called “virtual (software) instruments” modification of software programs.

conclusion cont d2
Conclusion (Cont’d)
  • Will NewTech replace/endanger traditional 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)!
conclusion cont d3
Conclusion (Cont’d)
  • New-Technology developments...maturity, critical mass, wide useprovide 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 d4
Conclusion (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!”…as it really matters.

  • National Science Foundation support (Grant No. CTS-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
you may contact prof kostic at
You may contact Prof. Kostic at:


or on the Web: