RTC Calibration program

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ijabbott
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Joined: Fri Dec 15, 2017 1:34 pm
Location: GB-MAN

Re: RTC Calibration program

Post by ijabbott » Thu Sep 05, 2019 10:33 pm

mcc wrote:
Thu Sep 05, 2019 4:54 pm
For me it is not totally clear from the instruction, whether I have to set the clock each time I do the calibration...
You just need to know how much it has lost or gained since the last calibration, and the date of the last calibration (assuming the current date set on the calculator is correct), and the previous calibration value. I find the easiest way to do that is to set the clock each time, and use the timestamp of the RTCCALIB.CFG file itself to record when it was last calibrated.

Mine has gained an additional 3 seconds in the 29 days since my previous calibration, which is about 1 ppm. So I should probably subtract 1 from my current calibration value and reset the time. I didn't bother with the program to determine this minor adjustment.

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