Hi,

In the Active Power Calculation section of ADE7953 datasheet, it is written that "With full-scale inputs, the expected reading in the AWATT and BWATT registers is approximately 4862401 LSBs (decimal)".

With full scale inputs 500mV , 1 LSB is equal to 0.5/6500000 = 7.692e-8.

For power calculations, RMS value is taken that is 0.5/sqrt(2)= 0.3535.

Multiplying current and voltage channels will be 0.3535*0.3535=0.124V. Then the expected reading with full scale inputs should be 0.124/7.692e-8 = 1624509. What is wrong with my calculation?

Thanks & Kind Regards,

Alper

Hi,

I would suggest looking at each register individually with its own conversion constant. For IRMS, VRMS and Power you find a A/LSB, V/LSB and a W/LSB respectively. There are some gains and bitshifts in the data path that don't allow you to just multiply the ADC output codes to get other registers down the line. Roughly speaking, from ADC output to RMS there is 1 bit shift and then from RMS to Power there is a bit shift of 24.

Regards,

Dlath