We are developing a high precision electric meter with ADE7880. As I attached the zero crossing section paragraph of datasheet, I did not understand how did you calculate the error of ZX detection as 0.0703° for 50 Hz with 80 Hz pole and 356 KHz clock frequency?
I wonder if you could explain or give a reference document, how we calculate it?
Mehmet Ali Ipin
The digital filter has a pole at 80 Hz and is clocked at 256 kHz.As a result, there is a phase lag between the analog input signal (one of IA, IB, IC, VA, VB, and VC) and the output of LPF1.The error in ZX detection is 0.0703° for 50 Hz systems (0.0843°for 60 Hz systems). The phase lag response of LPF1 results in atime delay of approximately 31.4°
typing error, not 356, should be 256 KHz..
These phase delays are inherent because of the digital filters (the LPF1), the values are obtained during the development of the silicon. Would you like to know more about phase calibration instead?
Thank you for your answer. Yes, May I kindly request you give information phase calibration of ADE7880 please? I can calibrate and measure the energy of course,
I know LPF components of Resistor-capacitor/inductor a little bit. But I lost myself between 3.3KHz LPF bandwith, 80 Hz pole, 256 KHz sampling rate, 50/60 Hz and phase lag. I would like to express my deepest gratitudes, as well, if you help me to understand ( document, application note etc.) .