if I using the ADE9078 in a 3-wire application, what values will be stored in the "xPeriod" registers ?
In the 3-wire delta system you specified at page 59 of the ADE9078 datasheet, we connect phase b to ground and actually there will be no waveform to B phase voltage ADC. But in some application, people still want to see the voltage between Phase A and Phase C wire, so the chip will recover a signal by Va and Vc in the data path. The chip calculate the frequency by detect if the voltage signal have a zero crossing situation. So the chip will still have value in BPERIOD register. The accuracy for calculating Vb’ is same because these 3 voltage(voltage between phase A and B, voltage between phase C and B, voltage between phase A and C) signal form a triangle. Every RMS or frequency calculation operation will be same for these there phase. I attach a picture of 3 wire delta system for you to understand it better.
my problem is to understand how the ADE measure the frequency.
For example, in the datasheet, page 59, 3 wire measurement, VCONSEL = 100, I have to connect phase b to ground.
So, I do not understand how the chip is able to measure a voltage at VB, or use the chip the value of Va' = Va-Vb and Vc'=Vc-Vb to calculate Vb' = Va'-Vc' ?
If the chip calculate Vb' do I have the same accuracy / resolution for the frequency ?
thanks a lot, now I can start with the schematic.
Retrieving data ...