Please help calculate aging offset value for ds3231 module

Projects Programming
1

It is about the ZS-042 module with DS3231 and EEPROM chip.

I did a drift check against reliable time source and my RTC is losing 0.17 seconds per day (slow). I lose 1 second in 6 days. So, I'm going to try and adjust the aging offset to hopefully get a slightly better accuracy than this.

I think 1 second in 6 days or 0.17 sec per day is about 2 ppm, right?

If so, should I put the aging offset to -20 to try and speed up the clock? I think the adjustment of "1" of aging offset value is equivalent to approximately 0.1 ppm.

Please help. Thank you.

2

I did a drift check against reliable time source and my RTC is losing 0.17 seconds per day (slow).

Is that consistent over a range of temperatures ?

3

JohnElectronics:
I think 1 second in 6 days or 0.17 sec per day is about 2 ppm, right?

If so, should I put the aging offset to -20 to try and speed up the clock? I think the adjustment of "1" of aging offset value is equivalent to approximately 0.1 ppm.

That sounds right to me - assuming the temperature stays between about 10C and 30C (see the graph in the datasheet)

Yours,
TonyWilk

4

UKHeliBob:
Is that consistent over a range of temperatures ?

Not sure. I'm running the clock in an apartment. The temperature is around 20 deg C.

5

If you are in an apartment and are exceptionally concerned about accurate timekeeping, the best option may be a radio controlled clock set by WWVB.

As long as WWVB continues to exist, and can reset the clock, the clock stands to gain or lose a second about every 30 million years.

6

the clock stands to gain or lose a second about every 30 million years.

You could probably compensate for that if you could measure it accurately enough, but testing it would be a lengthy process :slight_smile: