OSCAR and DST

[apneaeric]

       
I'm confused by what's happening to my OSCAR data from my AirSense 10 Autoset with the change to DST.

This morning when I loaded my data into OSCAR there were strange anomalies.
-It showed the end of my session at 7:08 am, when it was 8:08 DST. One might think this was just that the AirSense clock hasn't been changed, which it hasn't. But:

-when I look at the graphs for earlier in the night (see screenshot: OSCAR--diverging time indication.png), the times on the graphs do not coordinate with the time showing in the bottom bar. In the screenshot, the graph shows 2:01 and the bottom bar shows 1:01. (Sometime before morning this divergence disappeared. At the end of the session, both the graph time and the bottom bar time were the same. (Though, as noted above, not corrected for DST.))

-looking at previous day's data, the same divergence exists between the time shown on the graphs and the time shown in the bottom bar. Before last night, the two were in sync.

So something has obviously happened either with the AirSense or with OSCAR at the shift to DST, but rather than making a clean shift to DST (which hasn't happened), it has garbled previous data.

The computer, of course, switches to DST automatically. (MacOS Sierra 10.12.6). So maybe that's playing a role, but neither the times on the graphs nor the times on the bottom bar match the computer times.

I can't figure out the logic of what's happening.

[Crimson Nape]

Using OSCAR 1.3.1 on a Windows platform produced the same results as you.  After zooming in on a time period, the two time displays matched. The time stayed matched after I zoomed back out, as well.  Switching between days didn't cause any difference afterward either.  It seems to be an initial computer time glitch.


Update: After exiting OSCAR and trying it again, it produced the same error that the OP reported and would not synchronize the time.

[apneaeric]

P.S.: I have no idea if this is relevant, but I always run in airplane mode. No need to have my medical history out in cyber/cellular space.

[Crimson Nape]

Thanks for the information, but it doesn't have any bearing on this glitch. The different CPAP brands present a challenge trying to keep up with the time that should be reported.

[apneaeric]

I reset the clock in my Airsense 10 yesterday evening, and today's graph times and bottom-bar times are in sync.

Something obviously happened connected to the switch to DST.
-something in the Airsense? How would Airsense know about the switch but not know to change the clock setting? (Since I'm in airplane mode, Airsense would not receive any messages about the switch to DST.)
-something in OSCAR? Does OSCAR know about DST but get confused when it doesn't get the adjusted data from Airsense? Does OSCAR get information about the DST switch from the OS, or time information from the OS? and this somehow results in the glitch? Why does changing the time setting in Airsense affect how OSCAR handles the data?

OSCAR may be open source, but I certainly don't have the ability to go in and try to suss this out. It's all very intriguing, however. But good to know that resetting the Airsense time seems to put things back properly.

[Crimson Nape]

Until the AS11 was released, all earlier models of Resmed CPAPs relied on a "dumb" Date/Time clock chip on the motherboard.  By "dumb", I'm referring to the fact that it has to be manually set by someone and not obtain its information from other sources.  There is no provision for a time change to occur automatically.   Because of the way some CPAP brands handle the time and date, your computer's date and time are brought into play.   This is where the problem of mismatched times occur.  Currently, this time reporting error will only happen twice a year.   The best recommendation I can provide you is to just ignore those days' reported times.  Days on either side will be normal again.

One way I found to work around this issue is to turn off the DST option on the computer, purge that day is already imported, and then import the data into OSCAR. You can then turn on the auto-time or set it manually. So long as you don't re-import that day's data, it should report correctly.

[kappa]

The current OSCAR behavior is to take the timezone offset from when OSCAR is launched and use that for all imports of ResMed data. So if the timezone offset changes (i.e. you enter or leave DST) then OSCAR will load data differently once it is restarted. I do have a fix for this so maybe it's an appropriate time to try merge it in...

[Hmm888]

Now if there was only a way to help users who sleep past noon and Oscar. The Airsense 11 has this issue but the Airsense 10 did not with Sleephead.