Active Insulin Time (AIT) is actually a setting that the algorithm is using/calculating from to decide whether or not it’s safe to administer more insulin (e.g. micro-boluses). If you set the Active Insulin Time to 5 hrs (your current setting, for example) then every five minutes when the algorithm is calculating, it’s using all insulin that has been delivered in the last 5 hrs, and your Carb Ratios for that time, and your SG value, to decide whether or not more insulin is needed to get your SG value as close to 120 as possible within that 5 hr time period. TDD (total daily dose) also apparently plays a role in the calculation of the algorithm.
You can change AIT in combination with CRs (one or more CRs for different times of day, if needed) to enable the algorithm to behave more aggressively or less aggressively depending on the situation and your needs.
Hope this explanation helps. IMO we users still don’t fully understand how the algorithm operates completely at this point. Medtronic has kept a lot of the specs proprietary. Hopefully we will get more insight over time - it’s a new thing! Be patient when changing your settings - it takes time for the system to adjust!
But I love it so far…no lows in 3 weeks, calculated A1C of 5.9!!!