i am woerking on ADE7880 for energy meter development. i have done calibration of voltage and current at 300V,10A. at this point i change value of APGAIN register and do calibration of power also.All this at Unity power factor.
Now when i take reading at 300V,1A and 0.1 PF it seems to have 2 WATT difference in power(AWATT). as well as 1% error in current measurement and i cant understand Why ?
Same thing happens when i take reading at 10A,50V and 0.1 PF i found about 3 WATT difference in power reading(AWATT).
i read calibration data sheet of ade7880 but still i can't understand function of some of registers like AWATTOS, APGAIN, APHCAL. please explain in detail that how can i set values in this registers.