What to do When the Time Changes
Synching Pump Time to Loop Phone Time
For Loop users, the pump time should be in synch with the phone time so that you are getting the expected basal rate when you are disconnected from Loop. For Omnipod, there’s no choice but to set the time with the Loop app on the phone. For Medtronic, you should always use the Loop app to set the time on the pump. Do not adjust it on the pump itself.
For short trips you may choose to leave your basal rate on your “home” time zone. Just be aware of the Time-Zone Bug if you use FreeAPS.
Traveling across Time Zones or “Summer Time”
When you are traveling and change time zones, or when “summer time” starts or ends, you need to synch the pump to the phone time and this must be done using the Loop app.
To synchronize time on pump to the Loop phone time zone:
- Omnipod or Medtronic
- Change Time Zone
- Tap on the Change Time Zone button:
- Medtronic pump: modifies the time on the pump to current time on the Loop phone
- Omnipod: loads your basal schedule onto the pod based on the current time on the Loop phone – make sure phone, radio-link and pod remain in close contact until this step completes
For most people, an hour difference in basal rates probably won’t make much difference. Some people have drastically different rates at certain times to account for exercise such as swimming, and that hour difference can be important. Some people travel and leave their pumps on the home time.
Time Zone Bug for FreeAPS Users
If you make any changes to your Insulin Sensitivities while the pump and phone are out of sync, older versions of FreeAPS or versions newer than v2.1 (176) with Required Carb badge enabled, your app will crash and you will not be able to open the app again. This can happen if the time is changed for any reason, including routine travel.
WARNING: A rebuild will NOT fix this problem; you must first recover from the problem. Then later, you can build fresh to get the latest version of FreeAPS. With newer versions, turning off the Required Carb badge will prevent this issue.
If you encounter the Time Zone Bug, you can work around it with these steps.
- Note the time of the last CGM reading
- Power off the phone or shut off all communication with your CGM (airplane mode with Wi-Fi, cell and Bluetooth off as needed) long enough for the CGM data go to blank
- Wait at least 20 minutes and choose a time 1 minute past an expected CGM reading
- Try starting FreeAPS on the phone
- FreeAPS should now launch
- Enable Bluetooth (if disabled) so FreeAPS can communicate with your pump
- Go into FreeAPS / Settings / Pump / Change Time Zone
- If a CMG reading comes in before you complete this step, FreeAPS will crash again, and you’ll need to start over from Step 1
If it doesn’t work the first time (you get to the time change screen but do not get a response from your pump), power cycle your radio-link before trying again.
Loop master and automatic-bolus branches do not suffer this crashing problem if phone and pump are not in time sync.
Permanent fix for the Time Zone Bug:
As of March 21, 2021, the easiest way to address the Time Zone Bug before it happens is to rebuild FreeAPS using the Build Select Script. As long as the Required Carbs badge is disabled, you will not be impacted by the Time Zone Bug.