Instrumentation and Control Systems

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Instrumentationand Control Systems
ETP 2005 Brian Vance 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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Digital

• Using calculations by numerical methods or by
  discrete units

• http//www.m-w.com/

In digital technology the analog wave is sampled
at some interval and then turned into numbers
that are stored in the digital device. On a CD
the sampling rate is 44000 samples per second.
So on a CD there are 44000 numbers stored per
second of music. To hear the music the numbers
are turned into a voltage wave that approximates
the original wave.
http//www.howstuffworks.com/question7.htm
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Analogue

• Of a circuit or device having an-output that is
  proportional to the input
  

• http//web.ask.com/webo8001qsrc6qDefineAnal
  ogue

Analogue Data

• Can be any value within a defined range. An
  analogue sound level can have any loudness
  between zero and the maximum recorded as well as
  any frequencies between the highest and lowest
  recorded.

http//www.klbschool.org.uk/ict/gcse/theory/hardwa
re/analogue.htm
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Analogue Data

• Can be any value within a defined range. An
  analogue sound level can have any loudness
  between zero and the maximum recorded and any
  frequencies between the highest and lowest
  recorded.

http//www.klbschool.org.uk/ict/gcse/theory/hardwa
re/analogue.htm
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Examples of Analogue

• A traditional watch face is an analogue output

• A vinyl record is an analogue storage device

http//www.klbschool.org.uk/ict/gcse/theory/hardwa
re/analogue.htm
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The two big advantages of digital technology are

• The recording does not degrade over time. As long
  as the numbers can be read you will always get
  exactly the same wave.
• Groups of numbers can often be compressed by
  finding patterns in them. It is also easy to use
  special computers called digital signal
  processors (DSPs) to process and modify streams
  of numbers.

http//www.howstuffworks.com/question7.htm
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Binary

• Relating to being or belonging to a system of
  numbers having 2 as its base (binary digits 0 1)
• Involving a choice or condition of two
  alternatives (yes or no on or off)

http//www.m-w.com/
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Binary

• Binary (meaning two) is the ones and zeros that
  computers use.  The reason for this is that
  there are only two states an electrical circuit
  can be in. Known as on and off or 1 and 0 1 for
  on and 0 for off.

• By grouping 1s and 0s together a computer or
  electrical circuit can create letters numbers and
  True or False. Every bit of info in a computer
  has a binary code assigned to it and the computer
  knows these for example the letter A converts
  to 01000001 in binary.

http//homepage.ntlworld.com/interactive/
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Microprocessor

• Integrated circuit semiconductor chip that
  performs the bulk of the processing and controls
  the parts of a system

http//web.ask.com/webo8001qsrc6qDefinition
ofMicroprocessor
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Examples of Microprocessor-Based products

• Home appliances VCR Microwave etc.
• Cameras still video digital
• Automotive Comfort control ABS communication
  Engine control Trip computer
• Vending machines
• Industrial equipment Robots Machine tools
  Quality testing

http//www.hitech.technion.ac.il/bucher/mechatron
ics/course97/tsld014.htm
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Fuzzy Logic

• A form of mathematical logic in which truth can
  assume a continuum of values between 0 and 1
• http//web.ask.com/webo8001qsrc6qDefinitio
  nforFuzzyLogic
• Fuzzy logic is a superset of conventional
  (Boolean) logic that has been extended to handle
  the concept of partial truth -- truth values
  between completely true and completely false.
  It was introduced by Dr. Lotfi Zadeh of
  UC/Berkeley in the 1960s as a means to model the
  uncertainty of natural language.

http//www-2.cs.cmu.edu/Groups/AI/html/faqs/ai/fuz
zy/part1/faq-doc-2.html
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Examples of Fuzzy Logic

• Fuzzy logic is used directly in very few
  applications. The Sony PalmTop apparently uses a
  fuzzy logic decision tree algorithm to perform
  handwritten (well computer lightpen) Kanji
  character recognition.

http//www-2.cs.cmu.edu/Groups/AI/html/faqs/ai/fuz
zy/part1/faq-doc-3.html
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More Examples of Fuzzy Logic

• Regulating auto antilock braking systems
• Camera auto focusing
• Automating laundry machine operation
• Controlling Video camcorders image positions

http//www.usfca.edu/villegas/classes/992-6275/62
75ch18/sld043.htm
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Neural Systems

• Artificial intelligence used in systems to a
  variety of different things

http//www.robotbooks.com/robotic_lawn_mower_robot
_vacuum.htm
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Sensors

• A device that responds to a physical stimulus (as
  heat light sound pressure magnetism or
  particular motion) and transmits a resulting
  impulse (as for measure or operating a control)

http//www.m-w.com/
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Examples of Sensors
http//hpwren.ucsd.edu/ITR/vorb-design/smer_sensor
s_pres/pablo/img5.htm
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Actuators

• An actuator is a piece of equipment that produces
  movement when given a signal. Actuators are used
  in the computer control of an environment
  industrial automation and in robotics

• There can be tree types
• Electrical
• Hydraulic (work by liquid pressure)
• Pneumatic (work by air pressure)

http//www.school-resources.co.uk/Actuators.htm
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Examples of Actuators

• A valve in the greenhouse may be closed to
  restrict the flow of hot water through radiators
  and pipes.
• Another motor or actuator will lower blinds to
  reduce the amount of direct sunlight.

http//www.school-resources.co.uk/Actuators.htm
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Stepper Motor

• A motor whose driveshaft rotates in small steps
  rather than continuously

• http//www.m-w.com/

• Stepper motors are electromagnetic actuators
  that convert input pulses to output motion. They
  are different from ordinary current (DC) motors
  in that when energized by a voltage or current
  pulse train the step motor moves in incremental
  amounts for each pulse it reads.

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Examples of Stepper Motors

• Stepper motors are commonly used in computer
  peripheral equipment such as printers tape
  drives and disk drives. Additionally they are
  used in machine tool controls process control
  systems robots and other industrial applications.

http//bits.me.berkeley.edu/mmcs/PROPRNT3/STEPPER.
HTM
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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

• http//dictionary.reference.com/searchqsynchro
  

• The synchro is a type of rotary electrical
  transformer that is used for measuring the angle
  of a rotating machine
• The synchro was developed during World War II
  as part of a servomechanism that was used to
  synchronize the movement of a gun turret to a
  control dial.

http//www.mywiseowl.com/articles/Synchro
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Examples of Synchro Motors

• Defying gravity this window-climbing robot toy
  can easily scale smooth surfaces like windows
  mirrors and file cabinets. Using an ingenious
  system of four powerful suction cups our Wild
  Climber Tree Frogs precision release capability
  enables two feet to disengage and advance while
  the other two support its weight. The
  synchronized movement is a marvel to behold. For
  safety reasons do not use on ceilings or above
  head height. Requires two AA batteries. For age
  six through adult.

http//www.terrifictoy.com/store/tree_frog.html
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Open-Loop Control

• In an open-loop control the sequence of commands
  in the program is carried out irrespective of the
  consequences.

http//www.school-resources.co.uk/Automated_System
s.htm
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Examples of Open-Loop Control

• Switch a microwave on to defrost for 2 minutes.
  The turntable will turn and the food be
  microwaved for 2 minutes irrespective of whether
  it is thoroughly defrosted or not.
• Program a toy robot to walk in a certain
  direction. It will follow all instructions even
  if there is an obstacle in the way.
• Switch a sprinkler system on to water the garden
  at set times. Your garden will continue to be
  watered at these times even if it is pouring.

http//www.school-resources.co.uk/Automated_System
s.htm
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Closed-Loop Control

• A closed-loop control system is one that involves
  feedback to ensure that set conditions are met.

http//www.school-resources.co.uk/Automated_System
s.htm
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Examples of Closed-Loop Control

• Any system that attempts to maintain a constant
  temperature involves feedback
• Central heating and air conditioning systems
• Ovens
• Tropical fish tank
• Refrigerator
• Freezers

http//www.school-resources.co.uk/Automated_System
s.htm
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Instrumentation

• The use or application of instruments
  (as for observation measurement or control)

http//www.m-w.com/
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Examples of an Instrumentation

• Thermistors are thermally sensitive resistors and
  have according to type a negative (NTC) or
  positive (PTC) resistance/temperature
  coefficient.

http//www.thermometrics.com/htmldocs/proserv.htm
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Examples of Theristors

• Engine Management
• Information displays
• Climate control
• Circuit protection

http//www.thermometrics.com/htmldocs/proserv.htm
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More Thermistors

• Found in Appliances
• Washing machine
• Dishwasher
• Microwave oven
• Toaster

http//www.thermometrics.com/htmldocs/proserv.htm
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Standards Addressed

• Standard 2
• Benchmarks Y DD FF
• Standard 3
• Benchmarks H J
• Standard 17
• Benchmarks M O P Q