Guru
Joined: 21/06/2018
Location: AustraliaPosts: 1210
| Posted: 12:32am 25 Jan 2025 |
I calculated that your inverter is causing a 4.32 minutes error per 24 hours for a mains synched clock, which would annoy me also. Especially being a cumulative error.
Although the mains is not dead accurate over short periods I believe their brief is to ensure there are 5184000 cycles per 24 hours in US (4320000 here) and near midnight the generating authority play a little catchup or slow down to make it so.
I also calculate that the error you are seeing is the equivalent of a 36kHz error in the 12MHz oscillator, yes 100 times worse than a 30part per million initial crystal error. I believe that you can only "pull" a crystal by a few KHz with capacitors so maybe there is something else going on?
I suggest bread-boarding a bare minimum EG8010 circuit with a 12MHz crystal and start with your 60Hz tweaking (monitor SPWM 1 or 2 from memory) whilst nothing else is at play and go from there. If that magnitude of error is still there it points to a possible issue with the internals of the EG8010 ASIC code?
I have heard of people's digital clocks (mains synched) that gain time when their solar inverter is operating so some HF noise was maybe being seen as an extra Hz cycle from time to time, possibly waveform distortion with certain loads is tricking the clock ?
In my opinion you should be able to at least identify where the issue is or/and hopefully get it a lot closer than where you are now?
Edited 2025-01-25 12:09 by wiseguy