Design for Engineering Unit 4 Instrumentation and Control Systems Annette Beattie June 9, 2006 Instrumentation and Control Systems

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Design for EngineeringUnit 4 Instrumentation
and Control SystemsAnnette BeattieJune 9, 2006
Instrumentation and Control Systems

• ETP 2006 Annette Beattie
• This material is based upon work supported by the
  National Science Foundation under Grant No.
  0402616. Any opinions, findings and conclusions
  or recommendations expressed in this material are
  those of the author(s) and do not necessarily
  reflect the view of the National Science
  Foundation (NSF).

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Engineering

• The engineering profession is based upon
  mathematics and data.
• Design decisions and changes are ALWAYS based
  upon data that has been gathered.
• Data is gathered through instrumentation and
  control systems.

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Instrumentation and Control Systems

• Instrumentation - the act of using instruments
  for a particular purpose
• Ex. - instrumentation on a car dashboard -
  speedometer, odometer, oil gauge, temperature,
  etc.
• (ITEA/CATTS, 2003)

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Instrumentation and Control Systems

• Control - to keep within limits or to have power
  over
• System - a means of achieving a desired result.
  It has
• Input
• Process
• Output
• Feedback
• (ITEA/CATTS, 2003)

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Instrumentation and Control Systems

• System example - Car
• Input - driver puts it in drive, pressure on the
  pedal
• Process - transmission is activated, gas is sent
  to engine
• Output - car is ready to move forward, car moves
  according to pressure on pedal
• Feedback - PRND12 - the D is highlighted, the
  speedometer gives speed read out. We also
  receive feedback from warning lights on the dash
  to tell us if something is wrong with the car or
  if we need fuel.

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Instrumentation and Control Systems

• Control system - a system for controlling the
  operation of another system (dictionary.net,
  n.d.)
• Example - the dashboard in your car
• Example - the stereo in your car
• What is the control system?
• What is the system its controlling?
• What is the instrumentation?

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Closed-Loop Control

• One that involves feedback to ensure set
  conditions are met (school-resources.co, n.d.)
• Example - you turn on the radio,
• pick a station (input),
• listen to the song (process),
• you dont care for it (feedback),
• and decide to change stations (output)
• the loop continues picking another station until
  the feedback says to stay on that station. Or
  everyone else in the car is yelling at you, which
  is another kind of feedback.

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Open-Loop Control

• The system of commands are carried out regardless
  of the consequences. (school-resources.co, n.d.)
• Example - Sprinklers for a golf course programmed
  to come on at 600 am even if its raining.

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Binary

• The binary number system (aka base 2) represents
  values using two symbols, typically 0 and
  1.?Computers call these bits.
• A bit is either off (0) or on (1).
• When arranged in sets of 8 bits (or 2 bytes) 256
  values can be represented (0-255).?
• Using an ASCII chart, these values can be mapped
  to characters and text can be stored.?It's not
  magic, it's just math! (Ciske, n.d.)

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Binary

• Example - the word Tech Ed is written in binary
  code as 01010100011001010110001101101000001000000
  100010101100100 (Ciske, n.d.)

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Digital

• Conversion of information into binary bits of
  data for transmission through wire, fiber optic
  cable, satellite, or over air techniques. Method
  allows simultaneous transmission of voice, data
  or video. (Remote Satellite Communications,
  2006)
• Examples - a computer, a digital clock

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Analog

• Also spelled analogue, describes a device or
  system that represents changing values as
  continuously variable physical quantities.
• A typical analog device is a clock in which the
  hands move continuously around the face. Such a
  clock is capable of indicating every possible
  time of day. In contrast, a digital clock is
  capable of representing only a finite number of
  times (every tenth of a second, for example).
  (webopedia.com, n.d.)

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Analog vs. Digital

• In general, humans experience the world
  analogically. Vision, for example, is an analog
  experience because we perceive infinitely smooth
  gradations of shapes and colors.
• Computers are digital machines because at their
  most basic level they can distinguish between
  just two values, 0 and 1, or off and on.
  (webopedia.com, n.d.)

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Analog vs. Digital

• A converter is used to change analog information
  into digital information that a computer can
  understand.
• In turn, a different converter is used to convert
  digital information put out by a computer into
  analog data.

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Microprocessor

• A microprocessor -- also known as a CPU or
  central processing unit -- is a complete
  computation engine that is fabricated on a single
  chip.
• This is the first microprocessor ever invented -
  the Intel 4004. (Howstuffworks.com, n.d.)

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Microprocessors

• The first PC microprocessor was the Intel 8080.
  It had 6000 transistors.
• Todays processor for PCs is the Pentium 4. It
  has 42 million transistors. (Howstuffworks.com,
  2000)

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Fuzzy Logic

• A problem-solving control system method
• It provides a simple way to arrive at a definite
  conclusion based upon vague, ambiguous,
  imprecise, noisy, or missing input information.
• It mimics how a person would make decisions, only
  much faster. (Seattle Robotics Society, n.d.)
• Deals with reason that is approximate instead of
  precise. (wikipedia.org, n.d.)

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Fuzzy Logic

• For example, rather than dealing with temperature
  control in terms such as "SP 500F and "T
  lt1000F", terms like "IF (process is too cool)
  AND (process is getting colder) THEN (add heat to
  the process)" or "IF (process is too hot) AND
  (process is heating rapidly) THEN (cool the
  process quickly)" are used.
• These terms are imprecise and yet very
  descriptive of what must actually happen. Similar
  to how you would think and react in the shower if
  the temperature changed. (Seattle Robotics
  Society, n.d.)

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Fuzzy Logic

• Fuzzy truth represents membership in vaguely
  defined sets, not likelihood of some event or
  condition. To illustrate the difference, consider
  this scenario Bob is in a house with two
  adjacent rooms the kitchen and the dining room.
  In many cases, Bob's status is "in the kitchen"
  which is completely plain he's either "in the
  kitchen" or "not in the kitchen". (wikipedia.org,
  n.d.)

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Fuzzy Logic

• What about when Bob stands in the doorway? He may
  be considered "partially in the kitchen".
  Quantifying this partial state yields a fuzzy set
  membership. With only his little toe in the
  dining room, we might say Bob is 99 "in the
  kitchen" and 1 "in the dining room", for
  instance. No event (like a coin toss) will
  resolve Bob to being completely "in the kitchen"
  or "not in the kitchen", as long as he's standing
  in that doorway. Reasoning that is approximate
  rather than precisely deduced. (wikipedia.org,
  n.d.)

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Fuzzy Logic

• Fuzzy logic allows for values between and
  including 0 and 1, shades of gray as well as
  black and white.
• Fuzzy logic is used in air conditioners,
  dishwashers, elevators, video games, etc.
• It was also used to create MASSIVE (Multiple
  Agent Simulation System in Virtual Environment).
  It is computer animation and artificial
  intelligence software that was developed for the
  Lord of the Rings trilogy. (wikipedia.org, n.d.)

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Fuzzy Logic

• Fuzzy logic software was used to create award
  winning visual affects, particularly the battle
  scenes of Lord of the Rings.
• The software was also used in The Lion, the
  Witch, and the Wardrobe. (wikipedia.org, n.d.)

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Neural Systems

• A type of artificial intelligence that attempts
  to imitate how a human brain works.
• Rather than using a digital model, in which all
  computations manipulate 0s and 1s, a neural
  network works by creating connections between
  processing elements, as if computer neurons.
• The organization and weights of the connections
  determine the output. (Pcwebopidia.com, n.d.)

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Neural Systems

• Neural network systems are particularly effective
  for predicting events when the networks have a
  large database of prior examples to draw on.
• Strictly speaking, a neural network system
  implies a non-digital computer, but neural
  network systems can be simulated on digital
  computers. (Pcwebopidia.com, n.d.)

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Neural Systems

• Neural networks are currently used prominently in
  voice recognition systems, image recognition
  systems, industrial robotics, medical imaging,
  and aerospace applications. (Pcwebopidia.com,
  n.d.)

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Sensors

• A device that responds to a stimulus, such as
  heat, light, or pressure, and generates a signal
  that can be measured or interpreted. (St. Jude,
  2006)
• A significant change involves an exchange of
  energy, so sensors can be classified according to
  the type of energy transfer they detect.
  (Wikipedia.org, n.d.)

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Sensor Examples

• Thermal sensors
• Thermometers, thermostats, thermocouples
• Electromagnetic sensors
• Ohmmeter, voltmeter, metal detectors
• Mechanical sensors
• Altimeter, pressure gauge
• Motion sensors
• Radar gun, speedometer, odometer (Wikipedia.org,
  n.d.)

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Actuator

• A mechanism that puts something into automatic
  action.
• Examples -
• A mail delivery system that delivers email into
  the users mailbox
• A human - moving arms, legs, fingers
• A robot - that grasps parts and moves them
• Motors - used when circular motions are needed or
  a rack and pinion is used in conjunction to make
  a linear motion (Howstuffworks.com, 2000)

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Actuator example

• A model of an actuator (IX SCARA Applications,
  n.d.)

• http//www.intelligentactuator.com/media/m-ap-ix-0
  001_01.swf

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Actuator example

• Actuator used to open power door locks
• The hook at the end of the actuator rod moves up
  or down which mimics a person moving the knob up
  or down. (Howstuffworks.com, 2000)

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Actuator example

• Inside of the actuator
• The small electric motor turns the gears which
  move the rack and pinion which moves the actuator
  rod up or down. (Howstuffworks.com, 2000)

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Stepper Motor

• These are small electric motors that can spin
  quite quickly and can be started and stopped on
  a dime. Instead of moving continuously, they
  move is small, precise increments.
• Stepper motors are used to spin floppy disks.
• They are also used to move an ink jet printer
  head assembly back and forth. (Howstuffworks.com,
  2000)

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Synchro Motor

• A system consisting of a generator and a motor so
  connected that the motor will assume the same
  relative position as the generator the generator
  and the motor are synchronized
  (Thefreedictionary.com, n.d.)
• A synchro motor resembles a small electric motor
  in size and appearance and operates like a
  variable transformer.

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Synchro Motor

• Synchros are used primarily for the rapid and
  accurate transmission of data.
• They are used to move small dials to give
  read-outs. (Concord University, n.d.)

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Putting it all together

• Most manufactured cars today have around 50
  microprocessors.
• The following is a picture of the most important
  computer in a car which uses many microprocessors
  - the engine control unit (ECU).
  (Howstuffworks.com, 2000)

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Putting it all together
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Putting it all together

• It gathers data from many different sensors
• It uses closed-loop control to monitor the
  outputs of a system to control the new inputs of
  that system.
• It knows everything about
• Coolant temperature
• Amount of oxygen in the exhaust, etc.
• With this information it performs millions of
  calculations each second.
• This determines the best spark timing and how
  long the fuel injector is open, for instance.
  (Howstuffworks.com, 2000)

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Putting it all together

• The pins on this ECUs connector interface with
  sensors and control systems all over the car.
  (Howstuffworks.com, 2000)

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Other components in the ECU are

• An analog-to-digital converter is used to read
  the outputs of some of the sensors in the car,
  such as the oxygen sensor. The output of an
  oxygen sensor is an analog voltage, usually
  between 0 and 1.1 volts (V). The processor only
  understands digital numbers, so the
  analog-to-digital converter changes this voltage
  into a 10-bit digital number. (Howstuffworks.com,
  2000)

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Other components in the ECU are

• Digital-to-analog converters - Sometimes the ECU
  has to provide an analog voltage output to drive
  some engine components. Since the processor on
  the ECU is a digital device( a computer), it
  needs a component that can convert the digital
  number into an analog voltage. (Howstuffworks.com,
  2000)

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Sources

• Ciske. (n.d.). Retrieved June 9, 2006 from the
  website Nickciske.com
• Concord University (n.d.). Retrieved June 9, 2006
  from the website students.concord. edu
• Dictionary.net. (n.d.). Retrieved June 9, 2006
  from the website http//www.dictionary.net/contr
  olsystem
• Howstuffworks.com. (2000). Retrieved June 9, 2006
  from the website Howstuffworks.com
• ITEA/CATTS. (2003). Introduction to engineering
  units of instruction. Retrieved June 9, 2006 from
  the website http//www.vcsu.edu
• IX SCARA Applications. (n.d.). Retrieved June 9,
  2006 from the website intelligentactuator.com
• Pcwebopidia.com. (n.d.). Retrieved June 9, 2006
  from the website Pcwebopidia.com
• Remote Satellite Communications. (2006).
  Retrieved June 9, 2006 from the website
  Spidersat.net
• School-resources. (n.d.). Retrieved June 9, 2006
  from the website school-resources.co
• Seattle Robotics Society. (n.d.). Retrieved June
  9, 2006 from the website seattlerobotics.org
• St. Jude. (2006). Retrieved June 9, 2006 from the
  website stjude.org
• Webopedia.com. (n.d.). Retrieved June 9, 2006
  from the website webopedia.com
• Wikipedia.org, (n.d.). Retrieved June 9, 2006
  from the website Wikipedia.org

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Standards

• Standard 2 Students will develop an
  understanding of the core concepts of technology
• 2.Y The stability of a technological system is
  influenced by all of the components in the
  system, especially those in the feedback loop.
• 2.FF Complex systems have many layers of
  controls and feedback loops to provide
  information.

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Standards

• Standard 17 Students will develop an
  understanding of and be able to select and use
  information and communication technologies.
• 17.M Information and communication systems
  allow information to be transferred from human to
  human, human to machine, machine to human, and
  machine to machine.
• 17.Q Technological knowledge and processes are
  communicated using symbols, measurement,
  conventions, icons, graphic images, and languages
  that incorporate a variety of visual, auditory,
  and tactile stimuli.