speed sensor troubleshooting

Discussion in 'The Projects Forum' started by payal.kellyyy, Jul 7, 2011.

  1. payal.kellyyy

    Thread Starter New Member

    Mar 28, 2011
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    I am having some problem in a speed sensor..It is showing a low current on the plc(5.3mA).

    Please find attached the circuit diagram for the same.

    I have checked voltage across all the components of this sensor .Please find below the readings for the same:

    VR1=2.825V
    VR2=0.153V
    VZd2=8.54V
    VD1=0.66V
    VC1=8.52V
    VC3=1.982V


    OUTPUT CURRENT =10mA

    I have checked resistors also but could not figure out the problem can you help me in its troubleshooting? What all can be the possible reasons for low current in a speed sensor.

    Can you figure out in this that which component has failed in this circuit ?

    Waiting for good replies .
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
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    Where do you have this current? Are you talking about the power consumption of the sensor? According to the datasheet it's typically 5.3 to 5.9 mA.

    Or is it the output current? This depends on what you connect to the output as it is open collector.
     
  3. BillB3857

    Senior Member

    Feb 28, 2009
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  4. payal.kellyyy

    Thread Starter New Member

    Mar 28, 2011
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    but the capacitor does not seems to be bad since I had verified there values.
     
  5. shortbus

    AAC Fanatic!

    Sep 30, 2009
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    @payal.kellyyy- One thing you don't say about your sensor or show in the schematic, is what magnet are you using?

    If you are detecting a moving magnet, no problem.

    If you are just trying to detect a gear tooth or other iron object that is your problem. According to the data sheet that BillB3857 linked to you need to put a magnet behind the sensor in that type of use. Without the magnet your sensor won't generate enough of a output.
     
  6. KMoffett

    AAC Fanatic!

    Dec 19, 2007
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  7. payal.kellyyy

    Thread Starter New Member

    Mar 28, 2011
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    Dear Shortbus,
    In my sensor also we are using a magnet which is placed behind the Hall Ic.
     
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