Dual slope integration help

Discussion in 'The Projects Forum' started by Siyom, Aug 11, 2012.

  1. Siyom

    Thread Starter Member

    Aug 9, 2012
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    I'm trying to design a Dual slope integrator for a digital power meter,the problem i'm facing is that i dont quite understand how the dual slope integrator works.

    I know that it uses a fixed period of time to charge a capacitor with an unknown voltage and then uses a negative reference voltage to discharge it whilst tiiming the run down.
    1. What i don't get is whether the fixed period of charging is determined by the RC network or by the controller?
    2. I know once the run down phase begins,the controller counts the number clock pulses coming in,and then obtains the run down period from that,Its the whole resolution and sampling rate part i do not understand.
    3. How do you change the whole thing so that you'll measure current?Do you do it in the microcontroller or
    Please help
     
  2. SgtWookie

    Expert

    Jul 17, 2007
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    DickCappels likes this.
  3. Siyom

    Thread Starter Member

    Aug 9, 2012
    33
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    So the integration time is determined by your resolution,and not the RC network?
     
  4. Ron H

    AAC Fanatic!

    Apr 14, 2005
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    Here is another description of how the dual slope ADC works.
     
    jt6245 likes this.
  5. crutschow

    Expert

    Mar 14, 2008
    13,006
    3,232
    To measure current you can measure the voltage across a small shunt resistor in series with the current and calculate the current using Ohm's law.
     
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