My application uses 3-phase, 4 wire connection, with CT coil.
When I switched off the line voltage, the load was on, I still get the value from the line period register. I can verify that voltage zero crossing timeout flag was set, no voltage zero crossing flag, but I can still get non-zero value from the period register, although it was varied a lot, from 50Hz to 60 Hz. I wonder if it was caused by the line noise, ADE7880 setup, or something else. Ideally, the period register should be near zero when there was no line voltage input, is it right?
I also noticed that at above condition, there were no voltage zero crossing flags, but I can get the current zero crossing flags, since the load was added on the line. So I am not sure if the issue I experienced was caused by the current (load).
thank you very much for the help.