We are using the ADE7880 metering IC for our energy meter project. We need to display the power parameters for each individual phase and System Energy parameters.
For Active power, i am reading the xWATT registers and multiplying the read ADC count with 16 (2^4) and then multiplying with the scaling factor. In this case the error observed is with in our expected accuracy.
For Reactive power, i am configuring the harmonic engine and reading only the FVAR register. The read ADC count is multiplied with 16 (2^4) and then multiplied with the scaling factor. In this case, the error observed is 4 times more. I tried to change the multiplication factor from 16 (2^4) to 4 and then the error observed was with in the limit. Is this an expected behavior and the datasheet needs to be updated or am i missing something?
Almost the same behavior is observed with energy calculations. The error observed with Active Energy computation is within the limit while the error observed with Reactive Energy was too high (almost 200%). I had to divide the read ADC count (xFVARHR) with 4 to bring down the error percentage assuming the above theory to be correct.
Request you to please provide your suggestion in this regard at the earliest.