MECH 591: Lecture 1

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MECH 591Lecture 1

• Instrumentation and Measurements
• Introduction and Course Overview

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Today

• Who am I?
• General course information
• Objectives
• Tools
• Laboratory information
• What are your COOP experiences with Data
  Acquisition?
• Overview of different sensing systems
• Introduction to LabVIEW

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Contact information

• Anthony W. Duva
• Office Kingman 202a
• Office Hours Check Web (by appt.)
• http//myweb.wit.edu/duvaa
• E-mail duvaa_at_wit.edu (easiest)
• Phone [phone] (spotty)

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General Course Info

• Course Objectives
• Develop data acquisition and data reduction
  skills
• Refine the Mechanical design of experiments
  process
• Extend team building skills through laboratory
  projects
• Tools Used in This Course
• Excel, Word
• Lab View and ELVIS work station
• Your Mind

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Course Handouts

• All handouts are on Web CT and the web page
• http//myweb.wit.edu/duvaa
• MECH 591 Instrumentation
• You should have downloaded
• MECH591 Syllabus
• MECH591 Section (A) Handout Manual
• MECH591 Laboratory Information Package

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Laboratory Information

• Laboratory work will also be done in the lecture
  from time to time.
• Lab groups will be 2-3 students each and assigned
  randomly
• Exercises will utilize a variety of equipment and
  software, primarily Lab View
• Final project will include fabrication of the
  test set up and validation testing.

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Data Acquisition COOP Experience

• Please introduce yourself
• Name
• Year
• Area of concentration
• Any experience with sensing systems?
• Any specific sensors of interest?

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Measurement Fundamentals
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Types of Measurements

• 2 Basic Types
• Direct comparison to a standard
• Indirect comparison thru a calibrated system
• Why do we have standards and calibrated systems?
• Measurements quantify physical observations in a
  way that can be shared and duplicated by other
  people in other places.
• Standard Weights and Measures were first
  introduced to facilitate trade
• Standards were then applied to and by scientific
  endeavors

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Units of Measure

• 1832 Treasury Department introduced Standard
  Weights and Measures for the USCS
• Facilitate customs and trade
• International System of Units or SI was
  established during the French revolution
• 1960 11th General Conference on Weights and
  Measures formally established SI.
• Included standards for length, mass, time,
  electric current, thermodynamic temperature, and
  luminous intensity.
• 1971, 14th Conference add the mole as the unit
  for amount of substance

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Standards

• Length
• The distance light travels in a vacuum in
  1/299,792,458 of a second
• Speed of light therefore 299,792,458 m/s
• Mass
• Only measure still relying on a prototype
• Platinum-iridium weight kept at International
  Bureau of weights and Measures - Paris

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Standards

• Time
• Based on atomic research and the frequency of
  electromagnetic radiations
• Based on cesium 133 atomic radiation
• Temperature
• Primary reference was the triple point of water
  and the boiling point
• Current standards include fixed reference
  temperatures based on properties of various
  substances, Figure 2.1 and table 2.5 of text

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What is a sensor?

• Formal definition A device that receives and
  responds to a signal or stimulus (American
  Heritage Dictionary of the English Language)
• Informally, a sensor is a device that takes in
  information from the outside world. Based on the
  information, the sensor creates a signal on which
  a system can base a decision
• A sensor, thus, has an input and an output
• Usually, a sensor is tailored to a specific task

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What is a sensor? (cont.)

• In our case, a sensor will measure some physical
  quantity and convert it into some electrical
  signal (e.g., voltage, current)
• It is our job to select the proper sensor based
  on the application or system requirements
• In theory, you would also want to do something
  intelligent based on the signal (turn on a
  heater, sound an alarm, pass/fail an industrial
  part, etc)

MECH 591
System
Sensor
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The human nose

• Humans have 347 different types of odor receptors
  which respond to a single type of odorant
• A given smell will be a combination of possibly
  many different odorants
• Dogs have several thousand types of odor
  receptors and can resolve many different types of
  odors

To brain
R1
R2
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Smell sensors

• Machines can sense smell by observing the
  frequency of oscillation of a quartz crystal
  covered in a special plastic coating
• The coating absorbs certain chemicals (presumably
  related to the desired smell)
• The added mass changes
• the frequency of the
• quartz crystal

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The human eye

• The eye has a set of photoreceptor cells to
  convert light into nerve signals interpreted by
  the brain
• Rods are very sensitive (night vision)
• Cones are less sensitive but we have three types
  (color vision)

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Vision sensors

• Many types of vision sensors exist (CCDs,
  photometer, PMTs, etc)
• Operate on the same principle of transforming a
  photon into an electrical current

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Characterizing sensors

• What are some important quantities to know about
  a sensor?
• Sensitivity
• Resolution
• Accuracy
• Repeatability
• Reliability
• Response function
• Dynamic range
• Noise characteristics

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Sensing systems

• What advantages do sensors have over using a
  human?
• Repeatability - a sensors output can be very
  stable over time whereas a human may suffer from
  fatigue
• Reliability - a sensor usually wont need
  bathroom breaks, vacations, etc
• Harsh environments - a sensor can operate in many
  environments that humans would complain about
• Sensitivity - sensors can be significantly more
  sensitive than the corresponding human sense
  (although not always!)

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Machine vision for QC/QA
Decision FAIL
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Introduction to LabVIEW
GRAPHICAL PROGRAMMING
FOR ENGINEERS AND SCIENTISTS
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LabVIEW Goals

• Become comfortable with the LabVIEW environment
  and data flow execution
• Ability to use LabVIEW to solve problems
• LabVIEW Concepts
• Acquiring, saving and loading data
• Find and use math and complex analysis functions
• Work with data types, such as arrays and clusters
• Displaying and printing results

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Virtual Instrumentation Applications
A single graphical development platform

• Design
• Signal and Image Processing
• Embedded System Programming
• (PC, DSP, FPGA, Microcontroller)
• Simulation and Prototyping
• And more
• Control
• Automatic Controls and Dynamic Systems
• Mechatronics and Robotics
• And more
• Measurements
• Circuits and Electronics
• Measurements and Instrumentation
• And more

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The NI Approach Integrated Hardware Platforms
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Virtual Instrumentation With LabVIEW
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LabVIEW Module I Goals

• Understand the components of a Virtual Instrument
• Introduce LabVIEW and common LabVIEW functions
• Build a simple data acquisition application
• Create a subroutine in LabVIEW

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Section I

• LabVIEW terms
• Components of a LabVIEW application
• LabVIEW programming tools
• Creating an application in LabVIEW

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LabVIEW Programs Are Called Virtual Instruments
(VIs)

• Front Panel
• Controls Inputs
• Indicators Outputs
• Block Diagram
• Accompanying program for front panel
• Components wired together

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VI Front Panel
Front Panel Toolbar
Icon
Boolean Control
Graph Legend
Waveform Graph
Scale Legend
Plot Legend
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VI Block Diagram
Block Diagram Toolbar
Divide Function
SubVI
Graph Terminal
Wire Data
While Loop Structure
Numeric Constant
Timing Function
Boolean Control Terminal
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Controls and Functions Palettes
Controls Palette (Front Panel Window)
Functions Palette (Block Diagram Window)
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Tools Palette

• Floating Palette
• Used to operate and modify front panel and block
  diagram objects.

Automatic Selection Tool
Scrolling Tool Breakpoint Tool Probe Tool Color
Copy Tool Coloring Tool
Operating Tool Positioning/Resizing Tool Labeling
Tool Wiring Tool Shortcut Menu Tool

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Status Toolbar
Run Button Continuous Run Button Abort
Execution Pause/Continue Button Text
Settings Align Objects Distribute
Objects Reorder Resize front panel objects
Additional Buttons on the Diagram Toolbar
Execution Highlighting Button Step Into
Button Step Over Button Step Out Button
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Creating a VI Block Diagram
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Wiring Tips Block Diagram
Wiring Hot Spot
Click To Select Wires
Use Automatic Wire Routing
Clean Up Wiring
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Dataflow Programming

• Block diagram executes dependent on the flow of
  data block diagram does NOT execute left to
  right
• Node executes when data is available to ALL input
  terminals
• Nodes supply data to all output terminals when
  done

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Help Options

• Context Help
• Online help
• Lock help
• Simple/Complex Diagram help
• Ctrl H
• Online reference
• All menus online
• Pop up on functions in diagram to access online
  info directly

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Closing remarks

• Read Chapters 12
• Do Problems 2-1 thur 2-5, 2-8
• Lab Groups will be assigned randomly
• Go to the course website and familiarize yourself
  with it
• Copies of these slides will be available
• Additional On-line Resources At National
  Instruments
• http//zone.ni.com/devzone/cda/tut/p/id/6031teach
  ing