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LabVIEW/DAQ by Dr. M. Kostic LabVIEW - DAQ Data Acquisition Dr. M. Kostic NIU - Mechanical Engineering
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LabVIEW/DAQ by Dr. M. Kostic What is LabVIEW - G l VInstrumentEW l Virtual Instrument Engineering Workbench l Full-featured Graphical Programming Software l Designed for Instrumentation and Data Acquisition Watch NI Demo
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LabVIEW/DAQ by Dr. M. Kostic What is Virtual Instrument-VI l 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
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LabVIEW/DAQ by Dr. M. Kostic Virtual Instruments (VIs) Front PanelFront Panel – Controls = Inputs – Indicators = Outputs InputOutput BlockDiagramBlock Diagram –Accompanying "program" for front panel –Components "wired" together
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LabVIEW/DAQ by Dr. M. Kostic (sub) VI as an Icon
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LabVIEW/DAQ by Dr. M. Kostic Let’s switch to LabVIEW software and play.... Show some Examples...
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LabVIEW/DAQ by Dr. M. Kostic Lab VIEW Summary l Virtual Instruments (VIs) Front Panel Block Diagram Connector/Icon l Two windows to create a VI Panel window (I/O) Diagram window (Program) l Pull-down menus Controls menu to place controls/indicators (I/O) in Panel window Functions menu to place program nodes in Diagram window l All LabVIEW objects have pop-up menus l Nonexecutable VIs indicated by...
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LabVIEW/DAQ by Dr. M. Kostic DAQ or Data Acquisition
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LabVIEW/DAQ by Dr. M. Kostic l About plug-in data acquisition (DAQ) boards. l About the organization of the DAQ VIs. l How to acquire and display an analog signal. 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. DAQ Scope
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LabVIEW/DAQ by Dr. M. Kostic DAQ boards: n DAQ boards: F Analog I/O F Digital I/O F Counter/timer I/O DAQ library supports all DAQ boards n DAQ library supports all DAQ boards n LabVIEW uses the NI-DAQ driver-level software Data Acquisition System Components PLUG-IN DAQ BOARD: 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. COMPUTER with SOFTWARE: 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: SIGNAL CONDITIONING: Modify transducer signals to match DAQ board specs/ranges. Examples: amplification or attenuation, filtering, excitation, etc. TRANSDUCERS: TRANSDUCERS: Sense the measured quantities and change their properties or generate corresponding electrical signals. Examples: strain gage, thermocouple, accelerometer, potentiometer, etc. Data Acquisition - DAQ Data Acquisition - DAQ
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LabVIEW/DAQ by Dr. M. Kostic Transducers Sense Phenomena Produce Electrical Signal Examples: l Thermocouples, Thermistors l Strain Gauges, RTDs l Pressure Transducers, Load Cells l Accellerometers, Microphones l Potentiometers, Etc..
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LabVIEW/DAQ by Dr. M. Kostic Signal Conditioning Condition Transducer Signals Make Signal Suitable for DAQ Board Examples: l Amplification/Attenuation l Linearization/Calibration l Filtering l Multiplexing (up to 3,072 channels) l Isolation, Excitations, Etc.
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LabVIEW/DAQ by Dr. M. Kostic Typical DAQ Board Main Features: F Analog I/O (Input/Output) F Digital I/O F Timer/Counter I/O, Triggering Accuracy, Flexibility, Reliability, Expandability Typical Specifications: F Computer Platform:(E)ISA, PCMCIA, PCI, NuBus F Input Channels: 8-16 SEnd, 4-8 DIff F Max. Sampling Rate: 50-500 (1,250) kHz F Resolution:8-16 bits F Gains:1,2,5,10,20,50,100 Times Range: 2.5) 5, (0-5) 0-10 Volt
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LabVIEW/DAQ by Dr. M. Kostic DAQ Hardware & Software Configurations Hardware: F Setting DIP Switches and Jumpers for Particular Options/Applications F Newer and Plug-and-Play Boards are Software Configured F Cabling, Signal Conditioning, Terminal Blocks, etc. Software: F Set-up and Configuration Programs F Drivers: Interface between DAQ Board and Computer F DAQ Application Software (LabVIEW, C, Basic, etc.) K Data Acquisition K Data Analysis (Statistics, FFT, DSP, etc.) K Data Presentation (Graphing, Plotting, Tabulation, etc.)
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LabVIEW/DAQ by Dr. M. Kostic Analog Input Considerations Single-Ended vs. Differential Resolution Resolution Range Sampling Rate / Aliasing Averaging / Noise reduction Adequately sampled Aliased due to undersampling 8 3-bit ADC 16-bit ADC Time. 10 V range 12 bit resolution 1X Gain Aliasing.
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LabVIEW/DAQ by Dr. M. Kostic DAQ Software Architecture – Windows WDAQCONF.EXE LabVIEW for Windows DAQ Library VIs DAQDRV NI-DAQ for Windows DLL WDAQCONF.EXE DAQ Board Now, new operating systems and application software versions make CONFIGURATION ESEAR!
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LabVIEW/DAQ by Dr. M. Kostic Analog Input and Output VIs AI Sample Channel AO Update Channel
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LabVIEW/DAQ by Dr. M. Kostic Waveform Input and Output VIs AI Acquire Waveform AO Generate Waveform
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LabVIEW/DAQ by Dr. M. Kostic Digital Input and Output Write to Digital Line ReadfromDigitalLine Read from Digital Line WritetoDigitalPort Write to Digital Port ReadfromDigitalPort Read from Digital Port
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LabVIEW/DAQ by Dr. M. Kostic DAQ Summary l Identify I/O Signal Types: 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
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic The Art of Signal Sampling and Aliasing: Simulation with a LabVIEW ™ Virtual Instrument The Art of Signal Sampling and Aliasing: Simulation with a LabVIEW ™ Virtual Instrument " What We See is Not What It Is! " Prof. M. Kostic Mechanical Engineering Mechanical Engineering NORTHERN ILLINOIS UNIVERSITY
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic 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
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Signal/Sampling Resolution Sampling/Time Resolution (Speed) Signal / Magnitude Resolution
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic There is NO such thing as... …too large hard drive disk, or... …too large sampling resolution! Well praised... high-definition digital graphics and CD-quality music …are NOT good (true) enough!
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Under-sampling looses (important) wave details !Under-sampling looses (important) wave details ! But it also may change the wave form/shape due to Aliasing !But it also may change the wave form/shape due to Aliasing ! (Under)Sampling & Aliasing...
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Real measurements of a simple sine-harmonic How come this if the measured signal is a simple sine-harmonic wave?
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Sampled signal Real signal
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Sampled signal Real signal
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Sampled signal Real signal
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Stroboscope light Rotating disk (RPM) Sampling RPM with Stroboscope If RPM and Strobe speeds (frequencies) are the same the reference mark will appear stationary (ZERO aliasing) If the Strobe speed is faster If the Strobe speed is slower If the Strobe speeds is half of RPM, the disk will turn twice and the mark will appear stationary again!
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic NO Alias. Aliasing ZERO Aliasing
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Interactive Experiments... LabVIEW Virtual Instruments LabVIEW Virtual Instruments Internet Interactive Experiment Internet Interactive Experiment Animated Movie Animated Movie
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic Who does the future belongs to ?
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www.kostic.niu.edu © MCMXCIX* Prof. M. Kostic No Limits … No Limits … The Future Belongs To… … Whoever Gets There First NO SPEED LIMIT
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Prof. M. Kostic Mechanical Engineering Mechanical Engineering NORTHERN ILLINOIS UNIVERSITY Instrumentation with Computerized Data Acquisition for an Innovative Thermal Conductivity Apparatus
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Introduction 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!
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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
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Introduction (Cont’d) Computerized data acquisition hardware and LabVIEW development and application software...in engineering curriculum at NIU...starting with Experimental Methods I and II ME courses
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Objectives 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
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Objectives (Cont’d) To demonstrate, analyze and discuss: Engineering challenge -What is to be accomplished? Engineering challenge -What is to be accomplished? Mechanical and Electrical Design Mechanical and Electrical Design Instrumentation and Measurements Instrumentation and Measurements Computerization and Data Acquisition Computerization and Data Acquisition
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Engineering challenge: What is to be accomplished ? An innovative method and a novel research apparatus 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 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. to determine its dependence, if any, on shearing itself.
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Engineering challenge (Cont’d) 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.
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Mechanical and Electrical Design TC Apparatus The main test-section dimensions: D/d=2.598/ 2.488 in outer/inner cylinder diameters respectively D/d=2.598/ 2.488 in outer/inner cylinder diameters respectively with the 0.055 in thick gap, filled with the test-fluid in- between with the 0.055 in thick gap, filled with the test-fluid in- between
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Mechanical and Electrical Design (Cont’d) Main and Guard Heaters Outer Cylinder Inner Cylinder Bearing with Dynamic Seal
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Instrumentation and Measurements 16 Thermocouples 16 Thermocouples DC voltage drop (across the main heater and a precise current resistor for power meas.) DC voltage drop (across the main heater and a precise current resistor for power meas.) Set & control guard heating (Solid-state Relays) Set & control guard heating (Solid-state Relays) Set & control cylinder rotational speed (motor drive and tachometer-sensor) Set & control cylinder rotational speed (motor drive and tachometer-sensor) 1 2 4 3 2 1 3 3 4
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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 j Two CB-50 terminal blocks with NB-1 extensions 1 2 3 4 5 6 1 1 2 3 4 5 6
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AT-MIO-16DE-10 Data Acquisition Board E Series architecture Up to 100 kSamples/sec Up to 100 kSamples/sec 16 single-ended/8 differential channels, 12-bit analog inputs 16 single-ended/8 differential channels, 12-bit analog inputs two 12-bit analog outputs two 12-bit analog outputs 32 digital I/O channels 32 digital I/O channels two 24-bit, 20 MHz counter/timers two 24-bit, 20 MHz counter/timers
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Computerization and Data Acquisition feed-back control for DC motor-drive using a calibrated tachometer-sensor 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 solid-state relays for efficient and accurate feed-back control of guard- heaters’ power comprehensive over-heating protection comprehensive over-heating protection interactive and comprehensive monitoring for the kinematics and thermal steadiness of all processes and 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 convenience of increasing the number of thermocouple sensors for more advanced measurements
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Computerization and Data Acquisition (Cont’d)
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Conclusion One of the objectives...to utilize the latest powerful, yet inexpensive, technological developments: sensors and transducers, One of the objectives...to utilize the latest powerful, yet inexpensive, technological developments: sensors and transducers, data acquisition and control integrated boards, data acquisition and control integrated boards, computers and application software, computers and application software,...for research and teaching by example.
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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
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Conclusion (Cont’d) In addition this system allows for... easy modification and enhancement of so called “virtual (software) instruments”...by modification of software programs.
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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)!
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Conclusion (Cont’d) New-Technology developments...maturity, critical mass, wide use provide for new ways to improve engineering curriculum and enhance learning environment New-Technology developments...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 Either lack of use, or abuse of modern technological and computational tools NewTech should be our Slave, NOT our Master. NewTech should be our Slave, NOT our Master.
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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.
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Acknowledgment National Science Foundation support (Grant No. CTS-9523519). National Science Foundation support (Grant No. CTS-9523519). Graduate School of Northern Illinois University (NIU) Graduate School of Northern Illinois University (NIU) Department of Mechanical Engineering Department of Mechanical Engineering Mr. Haibo Tong, graduate student and Mr. Al Metzger, for mechanical design and fabrication Mr. Haibo Tong, graduate student and Mr. Al Metzger, for mechanical design and fabrication Mr. Bill Vickers, for electronics design and fabrication Mr. Bill Vickers, for electronics design and fabrication
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You may contact Prof. Kostic at: mailto: kostic@niu.edu or on the Web: http://www.kostic.niu.edu
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