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									       Training Hall Sensors - Content
0107




         Hall effect
            Physical basics
         Hall elements (electronical part)
            Selection guide
         Hall sensors (contain Hall elements
          and other components)
            Types




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                                                Edwin Hall:
         Applications                          Discovery 1879

         Current developments

1
       Hall Effect
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         Conductor in
            magnetic field      VHall
           1: Electrons
           2: Hall element
           3: Magnets
           4: Field lines
           5: Voltage supply




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2
                                        Source: Wikipedia
       Hall Effect
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         Amplitude of Hall voltage VH
           VH  k H  I  B
            kH: constant factor (depending on Hall element)
            I: current
            B: magnetic field strength
         Dimension of magnetic field strength „B“:
          1 Tesla = 104 Gauss (1mT=10 Gauss)




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         B field in a typical sensor
            Maximum (close to magnet): ~1-2 Tesla
            Toothed wheel (air gap 1.1mm): ~0.1 Tesla
3
       Setup Hall Sensor
                                         Hall element + Magnet
         „System“
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           „Head“
              Hall elements
              Magnet
                                                          „System“
              Support piece
           Print
              Printed circuit board
              Electronical components




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         Housing
         Cable/connector
                                            Subassembly
                                            housing + electronics
4
       Selection Guide Hall Elements
                        Property                Value
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                        Type of measurement     absolute
                                                differential
                        Output                  analogue
                                                digital
                        Frequency               static (0Hz to 20kHz)
                                                dynamic (a few Hz to10-20kHz)
                        Temperature rating      -40°C to 125°C
                                                higher
                        Choppering              not choppered
         Hall Element
                                                choppered
                        Rotational alignment    not necessary
                                                necessary




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                        Sensitivity             high (5mV/Gauss)
                                                low
                        Electrical properties   Offset
                                                Noise
                        Integration level       Programmable
                                                Self calibration
5                                               Interpolation
       Manufactures
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         Major manufactures:
           Allegro Microsystems
           Infineon
           Micronas
           Melexis Microelectronic Integrated Systems


         Differences in all properties mentioned before




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6
       General Setup
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                                                 Sensor „head“
                Toothed wheel
                                             (Hall element+magnet)


                                                      Output stage
               Amplifier             Logic
                                                     (e.g. push pull)
       Print




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                                Connector/cable


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       Differences Hall Sensors
                       Property                    Value                 Comment
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                       Number of Hall elements     1                     Speed
                                                   2                     Direction
                                                   3 or 4                Redundance
                       Output stage                analogue              seldom
                                                   digital (amplifier)   standard
                       Sensitivity                 air gap               approx. 0.5-3 mm
                                                                         (depending on target)
                       Structures to be detected   periodic              e.g. involute gear
                                                   not periodic          e.g. flat
        Hall-Sensors
                       Setup                       axial, radial
                                                   alignment necessary




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                       Temperature rating          high                  -40°C to 125°C
                                                   low                   -20°C to 85°C

                       Mechanical parameters       diameter
                                                   length
                                                   cable, connector
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       Speed- and Direction Detection
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         Speed: time from rising edge to rising edge
          (period time)
         Direction: Value of signal 1 at rising edge of
          signal 2




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9
       Jaquet Terms I
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         DSD:
           differential Hall element:
               Advantage: insensitive against magnetic disturbances
               Disadvantage: intermediate sensistivity, must be aligned
           1 up to 4 channels (for direction detection, redundancy)
           Main application: railway
         DSF:
           dynamical Hall element (not down to 0 Hz):
              Advantage: large airgap




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              Disadvantage: no zero speed detection
           Single channel
           Typical single speed channel: turbine of power plant


10
       Jaquet Terms II
         DSS:
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           Static Hall element:
              Advantage: zero speed detection, rotational symmetry
              Disadvantage: intermediate sensistivity
           Single channel
           Main application: industrial
         DSY:
           Static Hall elements:
              Advantage: zero speed detection, smallest 2 channel sensor
              Disadvantage: intermediate sensistivity, not for timing critical




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               applications
           2 Channel -> Direction
           Main application: hydraulics


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       Jaquet Terms III
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         DSL
            Low cost sensors (similar DSS)
         DSM
            For timing critical applications
         DSI
            Sensors with „intelligence“
               IQ (programmable sensor)




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               High resolution sensor

         FTG :
            Old name for Hall as well as VR sensors

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       Jaquet Terms IV
         Greenline: Standard sensors (catalogue)
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            D-Series:
               differential Hall element
               dynamic
               single channel
            E-Series:
               inductiv (coil)
               single channel
            F-Series:
               static




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               single channel
            Y-Series:
               static
               2 channels

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       Jaquet Terms V
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         Ending of sensor names: STV, PHWR,
          PHZ,....
           Z: analogue, 1 channel (no amplifier)
           V: digital, 1 channel („amplifier“)
           W: digital, „Quadrature“, 2 channels with phase
            shifted signals
           D: digital, 2 channels (1 speed, 1 direction)
           Particular „electronics“:




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              .17: DSD-V-version for railway applications (also
               redundant)
              .19: DSD-W-version for railway applications
              special applications: special voltage for low speed,
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               suppression of „wrong“ pulses, ...

								
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