# How to calculate o full scale voltage and current for ADE 7880?

Question asked by anur on Apr 19, 2013
Latest reply on Apr 27, 2013 by hmani

Hi all,

I am using ade7880 for energy metering.I am using a CT with max input current 63A and ratio is 1:252

To calculate values of registers like WTHR, VARTHR, VATHR, VLEVEL and VNOM, we require following values:

U,Ufs,I,Ifs.

Firstly i have a doubt what is U,Ufs,I,Ifs?

In my opinion :

U->nominal rms phase voltage (which i need to decide 220V/110V rms)

I->Nominal rms phase current (i need to decide--- say 10A rms)

Ifs->rms phase current for full scale adc input(63/root2---rms)

Ufs->?How to calculate Ufs?

Acc to datasheet -->Ufs and Ifs are rms values of phase voltages and currents when the ADC inputs are at full scale.

and U and I are nominal rms values.

Secondly:

How to choose The meter constant (MC, in impulses/kWh)-1600/3200/4800/arbitrary?

Thirdly,What is the value of constant----- n------ used in calculation of WTHR, VARTHR, VATHR?