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Energy meter ADE7755/68 with 8051

Discussion in '8051/8951' started by JeffreyPeter, Feb 3, 2013.

  1. JeffreyPeter

    JeffreyPeter New Member

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    I read about ADE7755 and understood its calculations. I am not clear about the Counter section and interfacing with microcontroller.
    If I designed an energy meter with 3200 imp/kwhr, should I count 3200 pulses for 1 kWhr ?
    Thanks in advance...
     
  2. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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    The way I read it is if you read a frequency of 2500 then the power is 2500 imp/kwh.. simple as..

    You don't have to count that... you can deduce the frequency in 1 second... They recommend 2 seconds to be accurate..

    I may be wrong..
     
  3. JeffreyPeter

    JeffreyPeter New Member

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    I actually have 3200 impulse/Kwhr as meter constant. Does it mean - 3200 pulse from CF pin = 1 Kwhr ... ?
     
  4. dave

    Dave New Member

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  5. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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    Like I said... The way I read it is.. If you have 3200 impulse / Kwh, then CF will have a frequency of 3.2Khz...

    You just need to measure the frequency... The text also said that the frequency on the CF pin is a tad unstable so sample for a minimum of 2 seconds

    If you count 6400 pulses per two second period and divide by 2... 3200 or 3.2Khz.
     
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  6. JeffreyPeter

    JeffreyPeter New Member

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    How to measure the frequency in 8051 pls explain a bit more... In some design I found the sampling at 10 sec what does it mean..
     
  7. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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  8. JeffreyPeter

    JeffreyPeter New Member

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    From datasheet,
    Average Freq = Counter/ timer
    => 6400 counts for 2 sec => 6400/2 = 3200
    Energy = Counter/timer * timer
    => 3200 * 2 = 6400.
    for our meter 3200 imp/kwhr so 2 kwhr...

    I am not sure about this calculation... what if I get less counts.
    for example count = 20 for 2 sec.
    Then how should I proceed with the calculation to get energy ??
    pls correct me if Im wrong..
     
  9. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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    It also said...


    So Doesn't that mean that the counter represents Watts?
     
  10. JeffreyPeter

    JeffreyPeter New Member

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    Yes It should be in watts... As meter constant is 3200 imp/kwhr, can't I count 3200 pulses from cf and account for 1 kwhr ?
     
  11. Ian Rogers

    Ian Rogers Super Moderator Most Helpful Member

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    I still reckon that 3200 = 3.2khz = 3.2KWh..... I may be wrong but thats what I'm seeing..

    You'll need to experiment with a know source.... Take a 40 watt bulb and measure that... see what the frequency is.... if its 40hz then you'll know..

    I was also looking at this..

     

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