position detectors

8/12/2019 Position Detectors

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POSITION DETECTORS


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POSITION DETECTORS

A position sensoris any device that permits

position measurement. It can either be an

absolute position sensor or a relative one

(displacement sensor). Position sensors canbe linear, angular, or multi-axis.
http://en.wikipedia.org/wiki/Sensorhttp://en.wikipedia.org/wiki/Sensor


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TYPES OF POSITION DETECTORS

Position sensors use different sensing

principles to sense the displacement of a

body. Depending upon the different sensing

principles used for position sensors.


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CAPACITIVE POSITION SENSORS

By changing dielectric constant

In this configuration, the body or its part

whose displacement is to be measured is

connected to the dielectric material between

the plates.


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CAPACITIVE POSITION SENSORS

By changing overlapping area

In this configuration, the body or its part whose

displacement is to be measured is connected

to one of the plates, the other plate remains

fixed.


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MAGNETOSTRICTIVE LINEAR POSITIONSENSORS

Magnetostriction refers to the effect wherein

a material changes its size or shape in the

presence of the magnetic field the material

due to the alignment of the magnetic

domains, within the material, with the applied

magnetic field.


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MAGNETOSTRICTIVE LINEAR POSITION SENSORS


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EDDY CURRENT BASED POSITION SENSOR

Eddy Currents are closed loops of induced

current circulating in planes perpendicular to

the magnetic flux. They normally travel

parallel to the coil's winding and the flow is

limited to the area of the inducing magnetic

field.


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HALL EFFECT BASED MAGNETIC POSITIONSENSORS

The Hall Effect principle states that when a

current carrying conductor is placed in a

magnetic field, a voltage will be generated

perpendicular to the direction of the field and

the flow of current.


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HALL EFFECT BASED MAGNETIC POSITION SENSORS


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FIBER OPTIC POSITION SENSOR

Optical fibers offer distinct advantages of

their immunity to EMI, inability to generate

sparks in potentially explosive environment.

Position sensors based on optical fibers canbe used for measurement ranging from few

centimeters to few meters where very high

resolution is not of paramount importance.


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OPTICAL POSITION SENSOROptical sensors are based one of the two

mechanisms. In first type, light is transmitted

from one end and received at the other.

Change in one of the characteristics-intensity, wavelength, polarization or phase-

by the physical parameter is monitored. In

second type, transmitted light is reflectedfrom the object and light returned towards

the source is monitored


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OPTICAL POSITION SENSOR

An example of second types of sensors is found on machine

tools measure the position of the work table is measured and

displayed.


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OPTICAL POSITION SENSOR

position detectors

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