Transcript Instrumentation and Control Systems

Instrumentation
and
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).
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
44,000 samples per second. So on a CD, there are 44,000
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
Analogue
 Of a circuit or device having an-output that is
proportional to the input
http://web.ask.com/web?o=8001&qsrc=6&q=Define+Analogue
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/hardware/analogue.htm
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/hardware/analogue.htm
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/hardware/analogue.htm
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
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/
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 1's and 0's 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/
Microprocessor
Integrated circuit semiconductor chip that
performs the bulk of the processing and
controls the parts of a system
http://web.ask.com/web?o=8001&qsrc=6&q=Definition+of+Microprocessor
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/mechatronics/course97/tsld014.htm
Fuzzy Logic
 A form of mathematical logic in which truth can
assume a continuum of values between 0 and 1
http://web.ask.com/web?o=8001&qsrc=6&q=Definition+for+Fuzzy+Logic
 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 1960's as a means to
model the uncertainty of natural language.
http://www-2.cs.cmu.edu/Groups/AI/html/faqs/ai/fuzzy/part1/faq-doc-2.html
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/fuzzy/part1/faq-doc-3.html
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/992-6275/6275ch18/sld043.htm
Neural Systems
Artificial intelligence used in systems to a variety
of different things
http://www.robotbooks.com/robotic_lawn_mower_robot_vacuum.htm
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/
Examples of Sensors:
http://hpwren.ucsd.edu/ITR/vorb-design/smer_sensors_pres/pablo/img5.htm
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
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.schoolresources.co.uk/Actuators.htm
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.
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
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/search?q=synchro
 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
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 Frog’s
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
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_Systems.htm
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_Systems.htm
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_Systems.htm
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_Systems.htm
Instrumentation
The use or application of instruments
(as for observation, measurement, or control)
http://www.m-w.com/
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
Examples of Theristors:
Engine Management:
Information displays
Climate control
Circuit protection
http://www.thermometrics.com/htmldocs/proserv.htm
More Thermistors
Found in Appliances:
Washing machine
Dishwasher
Microwave oven
Toaster
http://www.thermometrics.com/htmldocs/proserv.htm
Standards Addressed
 Standard 2
 Benchmarks Y, DD, FF
 Standard 3
 Benchmarks H, J
 Standard 17
 Benchmarks M, O, P, Q