Why does the 670g delete a calibration?

670g, Guardian sensor, manual mode

Last evening, 7:30 PM, did a calibration

Last night, 10 PM, did a calibration prior to going to sleep, afterwards the sensor status said the next required one was at 10AM this morning

This morning, 3AM, calibration required, looked at sensor status, it said previous calibration was 7:30 PM; it had completely gotten rid of the calibration that I did at 10 PM, turned sensor off because I was trying to sleep!

This morning, 7:20 AM, turned sensor back on again, calibration required, did a calibration.

Why did it delete the 10 PM calibration and make me do a calibration at some random time in the middle of the night? This has happened a number of times before, and it’s extremely irritating.


They don’t want us ‘over-calibrating’ these automated systems. That breaks stuff.
They want the thing to work on its own and detect if its not accurate and send warning to the user that the sensor is bad. But, it also might have detected that it was ‘off,’ and so asked for verification.

We succeed a lot of control in automated systems. That’s one of the things that makes them irritating. I find them pretty annoying, too.

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I have never had this happen in 4 years of using the 670g. Usually one of two things happen:

  1. The pump reports a calibration not accepted, it will toss it out or far more likely, it happens to me

  2. I fail to complete the calibration, it is that double yes.

then the third reason,

if the sensor is still in the first 24 hours after warm up it will sometimes dial back post calibration.

now my disclaimer.

I am a Medtronic ambassador. My opinions are my own. They did not pay me to say nice things. OK, they sent me a shirt and a cup but even I am more expensive than that.

I had this happen too. A similar scenario, made a point of calibrating before bed and then in the middle of the night it woke me up. I believe I was in the first day of sensor wear. So as RPhil2 mentioned, a shorter calibration time frame because of the new sensor may have been the cause in my case.
So frustrating to awake to a calibration request regardless of the cause!

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I am often requested to calibrate six hours later during the second 12 hours after a sensor change. Never noted if the previous calibration was deleted. I also recall a Recent 6 hour Calibration request after doing a 10 pm calibration to avoid being awakened during the night which was several days after a sensor change.

It happened one the second night also - woke me up at 2:30 AM this morning. Pretty much the same circumstances. This happens in the fourth day or so; it doesn’t happen on the sensor change. Nothing is reported about it deleting the ~10 PM calibration, and yes, the calibration was completed.

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