Libre Sensors

I would guess that from a computing hardware point of view there is only enough memory to record 8 hours worth of data ( which could presumably be stretched by reducing the frequency of recording).

So after 8 hours the oldest reading gets over written by the newest.

So if you read the meter every 4 hours you get 50% duplicate readings. Not a problem for decent software. Your long term records should show no gaps.
If you read the meter every 10 hours you get a 2 hour gap between sets of 8 hour readings.

tubamanandy said:

I think I may have answered my own question in that maybe the Logbook is only your manual readings ?

Click to expand...

The logbook stores the number displayed every time you scan the sensor. However, the graph line should show where you've 'been', regardless of when you last scanned (as long as you don't leave more than 8 hours between scans). An actual number is not stored in the logbook unless you've scanned.

Regardless of what you do, once it is attached to your arm, the way you the Libre works is to take a reading every 15 minutes (I think). The results of this reading are stored on the sensor. As @LittleGreyCat mentioned, the sensor has enough memory to store 8 hours of data. After 8 hours, the oldest data is overwritten.

When you scan the sensor, it does not take a reading: it downloads the last 8 hours of results to your reader, tells you in big numbers, the value of the last reading it took and updates the graphs to contain the last eight hours.

Due to this method of working
- if you scan less often than 8 hours, you will lose data
- if you scan more often than 10 minutes, you probably won't get new data

I would emphasise that the value of the Libre is not in the big "latest reading" number.
It is in those graphs, the history and the trend.

I use the Diasend app on conjunction with LibreLink which gives an ability to browse the graph seeing every value taken. You can get the same info by downloading the BG from LibreView but it's not as quick/easy.