Historical Sleepyhead data looks strange after travel to different timezone

[vas2000]

I traveled to London (from the Bay Area) on Feb 26th and changed the clock setting on my Resmed Aircurve 10 VAuto. The Sleepyhead Daily data for the nights that I used it in London seem ok but when I looked at the data prior to my travel date, the data now looks bizarre.

This is the original chart for the night of Thursday Feb 16th which I had captured while I was in the Bay Area (which shows that I used the machine for 7 hours and 10 min):





This is the chart that I now see in Sleepyhead for the same night (which shows that I used the machine for 14:20 which is for exactly double the amount of the actual time):



I see the same pattern for every night for which I used the machine in the Bay Area.

I am still in London. I exited from Sleepyhead and changed the timezone on my Mac back to my home timezone but the charts still look bizarre.

Is this a Resmed problem or is this a Sleepyhead problem? I would imagine most of the devices collect the data in UTC so I can imagine that the historical start time and end time might be different in Sleepyhead but this seems rather strange. 

How do I fix the data in Sleepyhead? I see a function to Rebuild CPAP Data. Would that take care of it? Does it do it from its own data or will it do it from my backed up data (which I do have on Dropbox)? 

Is there a way to avoid this in the future?

Thanks.

[TBMx]

I'm only guessing here - but it seems quite obvious that with the timechange in your device all data still kept in the internal memory is offset by that value.
In sleepyhead for the night you mentioned there should be - in that case - 2 sessions - 1 with the original time from the bay area (which you imported in sleepyhead before your travel) and the new one - corrected by the timezone which than seems to be a nap in the afternoon.

how to avoid? ... simply use the "don't import before this date" function from the preferences - import once just before the time-correction - set that very date in sleepyhead - change the time - keep on importing till the very last day of your travel - change the time back + set the "don't import before this date" in sleepyhead to the according date. you should be done. (and be prepared for messed up data if you "travel back in time" and by that take 2 naps at the very same time - I would avoid that situation for all costs!)

what interests me more is: what did you change in your machine? simply the time - or the timezone? that's a huge difference. (I would suspect the latter.)

[dzwiss]

This has happened to me also. If you go into data at the top and hit "rebuild CPAP data" it will correct itself.

[Crimson Nape]

Resmed's time can be set. . . unlike P-R's. The Resmed "day" is from noon to noon of the time/date that the machine is set to. You are basically 8-9 hours ahead of SF time. My recommendation would be to set everything to the locale time.

[pholynyk]

"Is this a Resmed problem or is this a Sleepyhead problem? I would imagine most of the devices collect the data in UTC so I can imagine that the historical start time and end time might be different in Sleepyhead but this seems rather strange. "

Resmed devices collect their data using local time. When you return to SF, be sure to set the time back before London time rolls into the next day, as you cannot set the date back.

In addition, SleepyHead seems to have a problem with Daylight Savings Time. If you keep track of your sleep/wake times this week, and then check them after the time change, I think you will see that they have slipped.

[Sleeprider]

When you return, you can rebuild data from backup. It should restore the original timestamps and won't overwrite newer data.

[vas2000]

Thanks for the suggestions. 

I got back from my trip and used the Rebuild Data function in Sleepyhead and that seemed to have sorted the problem out.

I ran into issues when I tried to change the clock back to California time (from UK time) - it complained about not being able to set a date/time in the past. I found some posts which indicated that I needed to Erase Data. Once I did that, that issue got sorted out.

I'm surprised that the machine does not have a way to change Timezone or between Standard and Daylight Savings Time.

I guess they need to change to tracking everything in UTC (which they apparently don't do per pholynyk).

[Sleeprider]

Things get really strange when crossing the dateline. I never change timezones on the machine because I don't care about that period of data. A couple hours is okay, but still completely unnecessary. I believe airline pilots on PAP that are required to demonstrate compliance are instructed not to change machine clocks.

Unrelated to CPAP, but if you want to drive an accounting department person nuts, submit an expense report with 2 evening meals on as you travel from Asia to the U.S. and arrive before you left.

[BAZZA]

I've never been able to get past the problems that arise when returning from Europe to the West Coast. My ResMed S9 will always tell me that I can't record data because there is already data recorded for that "day". (from the last night in Europe). It really is a huge PITA every time it happens, so I've resorted to using a different SD Card when on trips across more than a three-hour time difference, then going back to my main SD card when I return. When I upload both to ResScan, I can stitch them together for a seamless compliance report.

[BAZZA]

I've never been able to get my ResMed S9 to work correctly after returning from Europe to the West Coast, so I've resorted to using a different SD Card for any trip where I cross more than three time-zones. But even that can be fraught as the immediate last night's data is still in the machine's local memory. It really is a significant PITA to deal with, more so with the machine itself than with the ResScan software. Sometimes I just skip a night of CPAP use after getting back home as I'm too exhausted to deal with the stupid firmware in the machine that doesn't deal with time-zone changes.