testing MPU (Magnetic pickup unit)

Discussion in 'General Electronics Chat' started by qitara, Apr 8, 2015.

  1. qitara

    Thread Starter Member

    Jan 18, 2013
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    Hi guys

    What is the best way to test a magnetic pickup sensor ?.
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Guitar string?
     
  3. qitara

    Thread Starter Member

    Jan 18, 2013
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    I am talking about the types used on flywheels and teeth gears to measure rotation speed.
     
  4. Hypatia's Protege

    Distinguished Member

    Mar 1, 2015
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    Monitor the output while playing a strong magnet across the sensor (observing correct magnetic polarity, of course)...

    Best regards
    HP

    PS more detail will require more details ;):)
     
    Last edited: Apr 9, 2015
  5. qitara

    Thread Starter Member

    Jan 18, 2013
    87
    0
    The sensor is used to measure a shaft rotation speed. The MPU is installed on a bracket and takes the readings from the gear teath on the shaft.

    I am able to take the MPU apart from the bracket to test it but the question is how do i test it ?.
     
  6. wayneh

    Expert

    Sep 9, 2010
    12,087
    3,027
    Turn it on and see if it works?

    I'm not trying to give flip answers, but there's no way to give a detailed answer without more details of the situation. Power source? Model number? Sensor details? Photo?
     
    OBW0549 and Hypatia's Protege like this.
  7. qitara

    Thread Starter Member

    Jan 18, 2013
    87
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    The MPU model number is (3034572). It is directly connected to an input/output card on a micro controller board that works as a PI controller. I am able to replace the sensor and go ahead but what i want to know is a way to test these MPU's ?
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    If this is the type similar to used in automotive timing that measure flywheel crank teeth, then they are usually NPN open collector output, if so you need to place a 1k resistor from output to +vdc.
    Then use a piece of ferrous metal to pass in front and measure the volt drop across the resistor.
    The threaded barrel type also work this way.
    Honeywell make one 1GT101DC
    Max.
     
  9. qitara

    Thread Starter Member

    Jan 18, 2013
    87
    0
    Thanks for the replay Max.

    If i am right a magnetic pickup is just a coil coiled around a small magnet ?
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Often a little more to, it usually consists of a hall sensing circuit with transistor output, so usually some on board electronics.
    There is also non-ferrous detector types.
    Max.
     
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