You can review the documents for Loop, OpenAPS, and AndroidAPS on the Looped Facebook group. These documents are pinned at the top of the page.
This group contains several people with deep knowledge of these systems as well as a community of many users of each of the APS variations. The community serves as a great way to get the parts you need as well as help building and troubleshooting. People are generous with a strong pay it forward ethic. I believe you have to join the group to get full access.
Switching from Dexcom to Medtronic CGM was the biggest hurdle for me, but the Guardian 3 is a completely different system from Enlite, and like I say they seem to be about equal to my G5. If anything the Guardian3 has been less inclined to overstate lows, though they both do that, and the Dexcom has been dropping signal a lot more often. Dex insertion process is much simpler, one thing I really dislike about Guardian, but I can work with it.
The 120 target is a problem for a lot of people, but I see actual users reporting A1Cs of 5.9, which is lower than I usually achieve. I had a lot of frustration at high numbers when I was trying to get my first pump dialed in, and this seems to be similar, so I’m schooling my expectations accordingly. It seems to take at least 4-6 weeks before people feel like they’re starting to get it, and you do have to work at it. But I also see people posting BG graphs after indulging in things like strawberry milkshakes that are pretty amazing. I get the impression some of the frustration has to do with learning things that I already take for granted, like pre-bolusing, so I’m hoping some of the stuff I’ve learned by hanging out around here may give me a bit of a leg up.
Suzan, Yes it is my understanding that the 670G has a fixed target of 120 for automatic mode and cannot be changed. I suppose that was necessary to get FDA approval (making the pump less likely to cause hypoglycemia). Hopefully, the 670 will work so well that the next Medtronic pump can allow for adjusting the automatic target lower.
I hope they have a mobile option for viewing CGM soon. After using mobile the past months, I can imagine not having. I think they really missed an opportunity not having that. I don’t want to pull out my pump everyone I need to check my BS.
Can’t speak for you or others but I have no problems pulling my 670G pump out of a case to check things when I need to, which is not often since CGM accuracy is excellent, and my auto mode settings are, in my opinion, close to optimal. Took me couple weeks to reach this point but it was well worth it!
For 670G users – would it be possible to just turn on the auto mode every night when I go to bed, so I can target the 120 BG level for sleeping overnight, but then do more aggressive manual targeting during the day? Will the pump and CGM system still “learn” if I use it this way? I don’t want go higher on my A1C if I don’t have to, but nighttime lows (like in the 40s) and then subsequent highs (in the 200s) are still a problem area for me, and if I was closer to 120 throughout the night I would feel like the 670G was still worth it, even if I’m not using “auto” 100% of the time.
Which was your first pump back in 1985? I thought the 506 was the first, at least compact to wear. We’re 2 old timers I guess!
I have trouble covering a high rise after 30 breakfast carbs. I tried taking the bolus 1 hour before and that was the only thing that helped. If I wake up on the low side I cannot do this aa it is impractical for my lifestyle. Breakfast is at about 4:45am. I am a nurse and work in surgery.
I also have trouble with some lows on busy days where I just go back to manual so it shuts off the basal before I get too low. The auto doesn’t do this, it runs me down too low.
I can give more info if needed at a different time. I’m in the car to leave work right now.
Actually it’s Temp Basal that is fixed at 150. No other options. We were discussing it at my 2nd training session today (switched to auto, yay!) and the trainer advised using 150 an hour or so ahead of exercise (icon for temp is a little running-guy), otherwise just let auto mode do its thing.
Hm. It does have those settings. In my case the values are carried over from my previous pump when I set the 670 up for manual mode. They seem to be active; that is, when I tried doing a 0-carbs bolus (i.e., a correction) at a BG of 139 a little while ago, it said no bolus was needed, so the wizard does seem to be targeting 140. OTOH, the pump seems to be using basal adjustments to bring me down to 120 (122 right now) so the two parameters do seem to be operating independently. I’m going to be checking in with my trainers tomorrow, so I’ll ask about this. Still a newbie!
The first pump I went on was a 504 back in 1985 - bent needle days if you went through that awful experience!
Morning/wakeup time can be a challenge to manage as there is for many T1D a natural tendency for sugar level to rise before/at dawn. There are 2 configurable settings in auto mode (as you probably already know). AIT (Active Insulin Time) and CR (Carbohydrate Ratio), and both of these play a major role in how the algorithm for the 670G behaves. The first thing I tweaked, after my initial settings from the trainer/CDE was reducing AIT from 3 hours downward since there is only one timeframe you can set for that. Currently my AIT is 2 hours but YMMV (your mileage may vary). Carb ratio, the other configurable setting, in auto mode, is NOT not how we always understood it to be for manual mode operation (e,.g. the amount insulin we take in proportion to the amount of carbs it will cover). In Auto-Mode Carb Ratios are actually used by the 670G algorithm to dictate micro-bolus insulin delivery! You can configure different carb ratios for different times of the day, which is essentially what I tweaked to get my middle-of-night to dawn sugar level better controlled (currently I have 4 different time-of-day CRs configured but am still tweaking things!). I also sometimes at wakeup do an initial pre-bolus of insulin equal to about 10 carbs (some people refer to this as a "phantom bolus’. Then do my pre-breakfast bolus on top of that. But sometimes I skip my pre-breakfast bolus if I’m working out after breakfast.
Just some ideas/food for thought on what I did. The Medtronic 670g Users Facebook forum has a wealth of information and folks who have been using Auto Mode for quite some time - highly recommend you join that group!
My first pump was also the 504. I started pumping in 1987. I tried the “bent needle set” and quickly decided that pumping was not for me. Luckily the “soft-sets” with the plastic cannula had just come out. Once I tried that set, I quickly signed up for a pump.
I do remember the metal needle, but just for a short time. They had quick set or something shortly after.
Anyway, my Active Insulin is 5 hours, from the trainer because of lows. My manual pump was set to 4. What exactly does AIT do to the algorithm? I have a couple of CR, but I wasn’t aware of the effect on the microboluses. That’s great to know!
I sent a 670 back and got a replacement because I was low all the time and still getting microboluses when I was down below 70. I thought maybe I exposed it to x-rays at work. This replacement actually seems better. I had to act like a crazy person to get them to switch it out. But I’m glad I did because I didn’t feel safe with the original.
Thanks a lot!
(I just don’t do Facebook because my husband has me worried about the safety of our information and tracking issues, etc.)
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!!!
You really know quite a bit about this. Can you tell me if the AIT of 3 or the AIT of 5 is causes more aggressive insulin doses? I was trying to reduce with 5, but not sure that’s correct.
The lower the AIT the more aggressive the behavior of the algorithm should be. From my own experience with 670G auto mode that was the number I lowered first since it’s only ONE number and utilized 24 hours a day.
Carb Ratios can be set differently depending on the time of day and your patterns/needs.
Remember - it’s the combination of AIT, CR, SG (sensor glucose values), and TDD that all together influence how the algorithm behaves at different times of day. This is commonly referred to as the 670G learning you, so when you make a change it can take some time/few days for the impact (for better or worse) to be seen. So be patient with changes and seeing their effect although I know that’s hard to do!!!
Be sure to work with your trainer/CDE on these settings as you make changes to them. I also highly recommend uploading your data to Carelink and looking it the reports to see what effect the changes are having on your control, and trends and patterns. You should probably do that now to get a baseline before making any changes to your settings.
