ECE5320 Mechatronics
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ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and Actuators Topic: Infrared Non-Contact Temperature Sensor. Prepared by: Daniel S Stuart Dept. of Electrical and Computer Engineering Utah State University E:Dsstuart@cc.usu.edu. 3/10/2006. Outline. Reference list

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Prepared by daniel s stuart dept of electrical and computer engineering utah state university

ECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Topic: Infrared Non-Contact Temperature Sensor

Prepared by:

Daniel S Stuart

Dept. of Electrical and Computer Engineering

Utah State University

E:Dsstuart@cc.usu.edu

3/10/2006


Outline
Outline

  • Reference list

  • To probe further

  • Major applications

  • Basic working principle illustrated

  • A typical sample configuration in application (application notes)

  • Major specifications

  • Limitations

  • Where to Buy

  • Cost Information

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Reference list
Reference list

http://www.temperatures.com

http://www.edl-inc.com

http://www.raytek-northamerica.com

http://www.sensorsmag.com

http://www.manufacturingtalk.com

http://www.capgo.com

http://www.atcsemitec.co.uk

Chrzanowski, K. Noncontact Thermometry Measurement Errors, SPIE Polish Chapter, Warsaw, Poland, 2001, ISBN 83-904273-5-5.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


To explore further survival pointers of web references etc
To explore further (survival pointers of web references etc)

  • http://www.capgo.com/Resources/Temperature/NonContact/NonContact.html

  • http://www.atcsemitec.co.uk/irsensor.html

  • http://www.manufacturingtalk.com/news/qhi/qhi102.html

  • http://www.sensorsmag.com/articles/0106/17/main.shtml

  • http://www.temperatures.com/ncsensors.html

  • Baker, H.D. et al. Temperature Measurement in Engineering, Vol I., John Wiley & Sons, NY, NY, 1953. ( www.omega.com)

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major applications
Major applications

  • Process Control and Manufacturing Plants

    • Steel Forging

    • Ceramic and Glass Processing

  • Used when the object being measured is moving.

  • Used when there is a lack of good thermal contact

  • Used when the object is over 3400 degrees Fahrenheit

  • Also known as a radiation thermometer, spot radiometer,radiation pyrometer, etc.

  • Used when the thermometer cannot reach the object needed to be measured

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major applications1
Major Applications

  • For contact thermometers the thermometer must be at the same temperature as the object. This is not true with non-contact.

  • Used when contact with the object could change its temperature

  • Used when contact with the object could damage the product. (liquid, critical structure, etc)

  • Used to observe large areas of an objects overall temperature

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle
Basic Working Principle

  • New sensors use a focal plane array of sensors to be more accurate

  • All sensors use the basic law of physics known as Planck’s Law.

  • The sensors measure the thermal emission of the object. This is known as the Black Body Radiation

Photo from Raytek Corps

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle1
Basic Working Principle

  • As seen by the graph, a linear scale of black body radiation, as temperature increases the power density rises and wavelength shortens

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle2
Basic Working Principle

  • This understanding can best be understood using Planks Equation:

    E = 2*pi*c^2*h/(L^5(e^(h*c)/(L*k*t)-1))

    pi = 3.14

    c = speed of light = 3 * 10^8 m/s

    h = Planck's constant = 6.626 *10^-34 J-S

    k = boltzmans constant = 1.3805 *10^-23 J/K

    L = radiation wavelength = meters

    t = absolute temperature = Kelvin

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle3
Basic Working Principle

  • Two Methods of Measurement Used:

    • The measurement of energy emitted over the whole band spectrum. This provides one single power level. This is typical of spot sensors. The sensors require a narrow optical constrained region to make sure that the temperature is of the object only. This method can be thrown off if the spot is not directly on the object needing to be measured. This method can also be tricked by the surface emmisivity of the object being measured.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle4
Basic Working Principle

  • The other method uses measurement of radiation from two different spectral bands. The measurements are then compared. The surface emmisivity is less impactful in this method. Although, this method is typically more expensive to implement.

  • Either method depends on the application and use. Whether looking at quick changing objects or needing highly accurate results

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle5
Basic Working Principle

  • There are two types of sensors used. Although new types are in creation.

    • Quantum Detector:

      • Typically made of semiconductor crystals or ceramic material.

      • They rely on counting photons at certain energy levels that enter the sensor.

      • They provide wide even response, but are limited to certain wavelengths.

      • They respond very quickly to change in radiation output

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Basic working principle6
Basic Working Principle

  • Thermal Detector:

    • These sensors use common thermometers like thermistors

    • They rely on a known absorption rate of a material within the sensor.

    • The thermometers measure the characteristics of the surface influenced by external radiation.

    • These temperatures are highly accurate and cover a large range of temperatures.

    • They are not very sensitive to small change and are slow in detecting change in temperature

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


A typical sample configuration in application
A typical sample configuration in application

  • Film Manufacturer

    • Drying ovens dry the emulsive material on the film.

    • A problem exists in the temperature of the film. If the film is too hot the film can become brittle. If too cold the film can get stuck in the machinery.

    • Typically the temperature of the oven was used to govern the use of heat.

    • To be more accurate and to cause less problems the use of IR non-contact sensors can be used, because they sample the temperature of the actual product.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


A typical sample configuration in application1
A Typical sample configuration in application

  • Heated Rollers for material processing require that the rollers remain at a very constant temperature.

  • Traditionally, contact sensors are used as separate rollers to the main roller.

  • Problems arise with mechanical failures of the temperature rollers.

  • The thermometers are also inaccurate as there is a real time lag of temperature count

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


A typical sample in application
A typical sample in application

  • By using non-contact sensors, the sensors can be placed directly in line with the roller.

  • There is no physical contact so there is less chance of break down.

  • Non-contact sensors are quicker to sense temperature change since they do not have to change in temperature themselves.

Photo from

www.sensorsmag.com

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


A typical sample in application1
A typical sample in application

  • The fast response of non- contact sensors is useful in digital sampling and PID controllers.

  • The faster response of sensors leads ultimately to a faster response in system controllers. Since change in temperature of the equipment usually takes time as is.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications
Major Specifications

  • Sensor ranges of low cost sensors 0 - 1000 degrees Fahrenheit.

  • Sensor ranges of medium to high cost sensors range from 480 - 5430 degrees Fahrenheit.

  • Output from Sensors can vary greatly.

    • Some utilize simple analog output for use with separate pyrometers

    • Others use digital pulse output to encode output for use with digital control systems

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications1
Major Specifications

  • Some sensors utilize self adjusting and calibration systems to become greatly more accurate to an object with a set surface emmisivity and density.

  • Some sensors incorporate density calculation settings to get core temperature based of surface temperature

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications2
Major Specifications

  • Sensors can range in reading capability

    • Some offer set constant real time readout

    • Some offer intermediate readout that can be timed with motion conveyors

  • Sensor readout can be set

    • A sensor can be set to read a particular spot

    • A sensor can also be ambient sensing a whole area

    • Future sensors may be phaseable, allowing for the exact location of the spot to be moved on the fly

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications3
Major Specifications

  • Sensors vary on the range they can be accurate.

    • Low cost sensors typically are only accurate within a few inches to a foot

    • Medium cost sensors can extend out to meter ranges.

    • High cost sensors can reach out indefinite as cost goes up.

A photo from www.capgo.com

a typical layout of a sensor used

for intermediate reading

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Major specifications4
Major Specifications

  • Sensors used have varied wavelength capability:

    • Thermal pile has a wide response

    • Silicon Photodiode ranges 0.4 to 1.1 micrometers

    • Lead Sulfide ranges 1.0-3.0 micrometers

    • Lead Selinide ranges 1.0-4.5 micrometers

    • Pyroelectric film ranges 8-11 micrometers

    • Ceramics typical range through all these and up to 14 micrometers in wavelength

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Limitations
Limitations

  • Although ISO has set some standards, for the most part the industry has very few set standards for non-contact IR sensors as of yet. Because of this, wide use in the industry is slow to grow.

  • These sensors usually are only good if the object sensed has a very low thermal mass, else the sensor must incorporate additional circuits to calculate core temperature off of surface results

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Limitations1
Limitations

  • The objects surface emmisivity can greatly impact the accuracy of the sensor. If certain wavelenths pass through the object they may not be detected by the sensor. A good example of this is glass, where the wavelength range must be at the point where glass become visually opaque to the sensor.

  • Atmospheric gases and water vapor can change wavelength and sensed infrared spectrums. These natural filters can impact the accuracy of the sensor

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Limitations2
Limitations

  • The performance and accuracy of the sensor goes up with the price. One must make a compromise.

  • Local electrical circuits and backup circuits may need to be cooled if the sensed object is lower in temperature than the surrounding circuit radiation. In this case the sensors may need to be cooled.

  • The sensors may also need to be cooled if the object being sensed is a great deal away.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Where to buy
Where to buy

  • Raytek Corporation.

  • IR Con Incorporated

  • Mikron Instrument Company Incorporated

  • Exergen

  • General Electric

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators


Typical cost
Typical Cost

  • Extremely Low cost sensors range from 40 to 150 dollars.

  • Industrial Sensing Units Range from 800 to 15,000 dollars

  • Custom made sensors and space sensors range from 15,000 dollars and up.

ECE5320 Mechatronics. Assignment#1 Survey on sensors and actuators