Phew what a frustrating evening I had yesterday!
So I inserted the sensor for the Dex at about 4.20pm and left it for the 2 hours specified in the manual. It appeared to be doing what it was supposed to and hopefully the end of the 2 hour warm-up period would coincide with my pre-dinner bg testing so I could calibrate the Dex. Hmmm, good plan but Dexter (as I have now called him - yes he is a man!) had other ideas.
Two hours had passed and dinner was ready. It was 6.45pm and all I had on the screen was "???". I called the support guy at Advanced Therapeutics and he wasn't sure so he called the other support guy then called me back. He said it can take longer than 2 hours in some people (typical that it looks like I am one of them!). So I waited..........
We had already arranged to pop round to see a friend so off we went with me grumbling about my "dud" new machine.
Sitting chatting, at 8.50pm (four and a half hours after sensor insertion!!!) it asked me for 2 calibration bg tests, so I entered them and it registered them and put the value on the screen. "Yippee" I thought, "it works", at which point "???" appeared again. At 10pm it started working again and I got almost a full half hour of readings until - you guessed it - "???".
I went to bed at 11pm with "???" still showing. I woke about 6am and looked at Dexter. He had been working continuously since approx 2 or 3am. And is still going. I'll say that quietly, I don't want to jinx him.
I've put in another bg result to bring him up to speed and hopefully I am now on my way. At least when I change the sensor I'll know that this can happen and will be prepared, rather than having a newbie panic!!
I know it is only one night's readings but it appears that my dawn phenomenon starts at 6am and my bg goes up about 3mmol, then it falls again half an hour later. I'll see what happens tonight.
So as long as Dexter stays on best behaviour I think we will be best friends.