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IN THE NAME OF GODIN THE NAME OF GOD
Instrumentation Term ProjectInstrumentation Term Project
Supervised By: Dr. Supervised By: Dr. HamidHamid D. TaghiradD. Taghirad
Magnetic position sensor
Ehsan PeymaniGolnaz Habibi
Magnetic Sensor
Feature of Magnetic Sensors
Advantage- Contact less- Unaffected by Contamination
Disadvantage- affected by other magnetic field
Position sensing ( all types )
CapacitiveEddy currentOpticalInductiveResistiveSonarLaserMagnetic
All Types of Magnetic Position Sensor
Hall effect sensorMagnetostrictiveMagnetoresistiveBase on Seismic theory Reed switchSynchro & ResolverInductosynMagnesynMagnetic encoderLVDT & RVDT
Special application
CompassingGPS navigationVehicle detection
Special applicationCompassing
Special application Compassing
Special application Compassing
Special applicationGPS navigation
Special applicationGPS navigation
Special applicationVehicle detection
Special applicationVehicle detection
Special applicationVehicle direction
Smart position sensor
Smart position sensor
Specifications :
Magnetostrictive LDTSmall & InexpensiveLinearity+/- 0.05% of StrokeAccuracy+/- 0.1% of StrokeRepeatability+/- 0.01% of full strokeOperating Temperature-20° to 70° C Programmable
Hall Effect Sensor
Hall effect : Dr. Edvin Hall , 1879Johns Hopkins University
Hall sensor : Joe Maupin & EverttVorthmann , 1965
Hall effectGeneral features
• True solid state• Long life • High speed operation - over 100 kHz
possible• Operates with stationary input (zero speed)• No moving parts• Logic compatible input and output• Broad temperature range (-40 to +150°C)• Highly repeatable operation
Hall effectTheory
Hall effect
Theory
tBIKV H
H =
Hall effect
Theory
Hall effectConditional Circuit
GVVS µ7=
!!! Silicon exhibits the piezoresistance effect
Hall effectConditional Circuit
Hall effectDigital Hall sensors
Hall effectAnalog Hall sensors
Hall effectMagnetic system
Unipolar head-on modeUnipolar slide-by modeBipolar slide-by modeBipolar slide-by mode (ring magnet)
Jump to Application
Hall effectMagnetic system
Unipolar head-on modeNonlinearAccuracy medium
Hall effectMagnetic system
Unipolar slide-by modeNonlinearAccuracy lowSymmetric
Hall effectMagnetic system
Bipolar slide-by modeAccuracy mediumDissymmetry
Hall effectMagnetic system
Hall effectMagnetic system
Bipolar slide-by mode (ring magnet)
Hall effectMagnetic system comparison chart
Hall effectApplication – Vane operated position sensors
Hall effectApplication – Vane operated position sensors
Hall effectApplication – Other in position
Sequence sensorProximity sensorOffice machine sensorsMultiple position sensorAnti-skid sensorPiston detection sensor
Hall effectApplication – Sequence sensor
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Hall effectApplication – Proximity sensor
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Hall effectApplication – Office machine sensors
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Hall effectApplication – Multiple position sensor
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Hall effectApplication – Anti-skid sensor
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Hall effectApplication – Piston detection sensor
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Magnetostrictive sensors
Invent at 1970 MTS Temposonictechnology
Theory of Magnetostrictive sensors
Manetostrictive effectVillari effectWiedemann effect
Theory of Magnetostrictive sensorsManetostrictive effect
Theory of Magnetostrictive sensorsVillari effect
Reverse of Magnetoestrictive
applying stress to a magnetostrictive material
changes its magnetic properties
Theory of Magnetostrictive sensorsWiedemann effect
Theory of Magnetostrictive sensorsThe operation
Theory of Magnetostrictive sensorsThe operation
Magnetostriction sensorsFeatures
Non contactAbsolute10 mm ~ 20 mNonlinearity < 0.02%
Magnetostriction sensorsComparison
Magnetostriction sensorsApplication
1. Automated (Robotic) ManualTrans ission2. Automotive Suspensions3. Automotive Steering4. Medical Hospital and Home Care Bed5. Medical Infusion Pump6. Medical Dental Chairs7. Tractor Steering8. Commercial Appliance Damping9. Automotive Tank Levels10. Construction Equipment
Magnetostriction sensorsApplication – Automated (Robotic) ManualTrans ission
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Magnetostriction sensorsApplication - Automotive Suspensions
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Magnetostriction sensorsApplication - Automotive Steering
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Magnetostriction sensors
Application - Medical Hospital and Home Care Bed
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Magnetostriction sensorsApplication - Medical Infusion Pump
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Magnetostriction sensorsApplication - Medical Dental Chairs
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Magnetostriction sensorsApplication - Tractor Steering
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Magnetostriction sensorsApplication - Commercial Appliance Damping
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Magnetostriction sensors
Application - Construction Equipment
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Magnetostriction sensorsApplication - Automotive Tank Levels
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Magnetoresistive sensors
Invent at 1856William ThompsonLord Kelvin
Magnetoresistive sensorsAll types
Anisotropic Magnetoresistive (AMR)
Giant Magnetoresistive (GMR)
Colossal Magnetoresistance (CMR)
Magnetoresistive sensorsTheory of AMR
Magnetoresistive sensorsTheory of AMR
θ2cos
Barber Pole Bias
Magnetoresistive sensorsTheory of AMR
Magnetoresistive sensorsOperation of AMR
Magnetoresistive sensorsOperation of AMR (HMC1501)
Magnetoresistive sensorsOperation of AMR (HMC1501)
Magnetoresistive sensorsOperation of AMR (HMC1501)
Magnetoresistive sensorsOperation of AMR (HMC1512)
Magnetoresistive sensorsOperation of AMR (HMC1512)
Magnetoresistive sensorsOperation of AMR (HMC1512)
Magnetoresistive sensorsOperation of AMR (HMC1512)
Magnetoresistive sensorsTypical application
Cylinder position sensing in pneumatic cylinders Elevator sensor Lid sensor for laptop computers Position sensor for materials handling equipment (lift trucks) Blood analyzer Magnetic encoders
Magnetoresistive sensors
Comparision of Hall effect & MR technologies
Magnetoresistive sensorsGiant Magnetoresistive (GMR)
Observe at 1988Magnetoresistivity > 70%
Magnetoresistive sensorsGiant Magnetoresistive (GMR) - Theory
Magnetoresistive sensorsGiant Magnetoresistive (GMR) - Application
Proximity DetectionDisplacement SensingRotational Reference Detection
Colossal Magnetoresistive (CMR)
Observe at 1988Magnetoresistivity > 1000% ~ 10000000%
Magnetoresistive sensorsComparison
Reed switch
Reed switchStructure
Reed switchAdvantages
Long lifeSmall sizeVery sensitive to magnetic fieldsHas no leakage current or voltage dropVery inexpensiveHighly repeatable operation High immunity to dirt and contaminationZero power consumption
It is electronically noisySlow response timeLarge amount of hysteresis
Reed switchDisadvantages
Synchro & Resolver
A device called Selsyn was developed at 1925
SynchroTheory
Synchro is variable rotary transformer.
SynchroClassification
Transmitter
ControlTorque
SynchroClassification
Receiver
ControlTorque
SynchroClassification
Differential Transmitter
ControlTorque
SynchroClassification
ControlTorque
SynchroAdvantages
The controlling unit can be along distance from the controlled unit.Low consumption.Eliminates the necessity of mechanical linkage.Continues accurate and visual information.Good reliability and minimum maintenances .Small and light.Very fast.
Resolver
ResolverTheory
Signal Conditioning
Resolver-To-Digital Converter(RTD /RDC)BasicUndersamplingOversampling
RTDBasic
.
RTDUndersampling
RTDUndersampling
RTDOversampling
OversamplingTMS320F240
ResolverAdvantages
Accurate Absolute Position SensorSmall sizeWell-suited to severe industrial environmentsNot require ohmic contact.High reliability
Synchro& ResolverApplication
Naval weaponsRadar antennasAerospaceRobotics
Inductosyns
Inductosyns types
Linear inductosynRotary inductosyn
Linear inductosyns
inductosynsSpecification
Use RTD for signal conditioningLinear resolution is 5microinch.angular resolution is less than 0.9 arc secondsrelatively expensivevery high accuratevery reliable
inductosynsAdvantages & Disadvantages
AccurateSmall sizeWell-suited to severe industrial environmentsNot require ohmic contactHigh reliability but relatively expensive
Magnesyn
MagnesynStructure
Magnetic encoderAll types
LVDT & RVDT
End of World War II
Linear Variable Differential Transformer(LVDT)
PRECISION ABSOLUTE VALUE CIRCUIT(FULL-WAVE RECTIFIER)
LVDT & RVDTComparison
LVDTMeasurement ranges are ±100µm to ±25cmSensitivity is 2.4mv per volt per degree of rotationInput voltages are from 1V to 24V RMS, with frequencies 50Hz-0kHz
RVDTTypical RVDTs are linear over a range of about ±40ºSensitivity is 2 to 3mV per volt per degree of rotationInput voltages in the range of 3V RMS at frequencies between 400Hz and 20kHz.
Advantages
Infinite ResolutionHigh accuracy and sensitivityExcellent linearity ( 0.5%)A wide variety of measurement ranges
LVDT
Application
Modern Machine-toolRoboticsAvionics & aircraftProcess control industryTorpedo, and weapons systems.
Thank you