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time difference between machine and software - sheepless - 08-13-2019
fyi, I've just started noticing the total daily usage time displayed on my resmed aircurve 10 asv is longer than reported by oscar and SH. sometimes there are differences between time reported in oscar and SH which may be the result of oscar combining close sessions (SH 1.0.0 beta 2 does not, unless set to do so in preferences), but I don't immediately see a reason for the disparity between the machine and the reporting software. in the instances I've checked, the machine displays usage at about 4-6 minutes longer than oscar and SH. for example, for last night the machine displays 8:30 while oscar reports 8:25:42 and SH reports 8:25:10. I assume the difference between oscar and SH in this case is just a rounding issue but I wouldn't expect rounding to explain the 4+ minute difference between the machine and the software.
has anyone else noticed this?
RE: time difference between machine and software - Crimson Nape - 08-13-2019
Do you have the Ramp turned on? If so, How long is it set for?
RE: time difference between machine and software - sheepless - 08-13-2019
no ramp but good point. sometimes / often / always (not sure which but for every session last night) graphical pressure info in both programs takes up to maybe 50 seconds from the time the machine is on to when the pressure waveforms appear. since my sleep is fragmented and I often have many sessions (8 mask off's last night), those intervals add up to about the amount of the discrepancy. I mentioned this gap some time ago in another thread but didn't make the connection this time. now that you might have solved that conundrum, any idea why the pressure graph doesn't appear until 10's of seconds after the rest of the graphs start recording?
RE: time difference between machine and software - pholynyk - 08-13-2019
I know that one! There's code in the import functions to drop the first twenty seconds of each session - It seems to take a while for the pressure to build up.
I don't know if that's a feature (the dropping of the first twenty seconds) or an issue...
I couldn't a four minute difference from that until you mentioned eight session is one night. (Resmed only allows for ten in a one day STR record, so I'll be interested to see what happens if you hit eleven or twelve...)
RE: time difference between machine and software - Crimson Nape - 08-13-2019
I've noticed that the Resmed uses a "Soft-start" feature that increases the pressure at the rate of 1 to 2cm per second up to the starting pressure. This occurs regardless of the Ramp feature. I often wondered if it includes this pressure-up time in its data set. . . That along with the time period of the "cool-down" feature when using the Climateline hose.
RE: time difference between machine and software - sheepless - 08-13-2019
pholynyk, I didn't have to look far to find 2 recent nights that include 11 and 12 sessions. there's a small difference between the 2 programs, I assume due to oscar combining close sessions. I have no way to compare them to the machine display since that only appears daily. if that's important I'll try to remember to compare next time I have more than 10 sessions. meanwhile, is there something else you'd like to see in those over-10 session charts or files?
RE: time difference between machine and software - sheepless - 08-13-2019
Crimson Nape, that makes sense to me; it's my impression the pressure graph doesn't start while it's building up to pressure. in fact, that rings a bell; maybe that's what I was told when I mentioned this a while ago; my never-very-good memory has suffered over the years, perhaps from decades of untreated apnea.
fwiw, I may have miscalculated in haste and I'll need to pay more attention but I'm pretty sure some of these gaps before the pressure waveform appears have been 30-50 seconds, i.e., longer than 20. I'll try to remember to check this for a while.
RE: time difference between machine and software - sheepless - 08-14-2019
fyi, for 7 sleep sessions last night the lag between when flow rate and pressure graphs begin was 1 each at 38 and 42 seconds and the rest were 41 seconds. assuming some read and arithmetic error it might be safe to assume the lag I'm seeing is 40 seconds.
times 7 = 4.67 minutes or 4:40. the difference between machine and software reported time last night was 3:50. (machine: 11:00; software: 10:56:10)
RE: time difference between machine and software - sheepless - 08-15-2019
I don't want to beat this thing to death but thought I should report that it doesn't appear the gap between when the flow rate and pressure graphs begin explains the time difference reported by the machine and the software after all.
9 sessions last night. for every one the lag before the pressure lines appear in the graph was 41 seconds. where I place the cursor leaves some room for error and I did not include the fractional seconds in figuring the arithmetic, so let's call it 40 seconds. 40*9=360 seconds or 6 minutes.
time reported by the machine: 10:25. time reported in oscar and SH: 10:23:10. difference: 1:50. vs 6:00.
1:50 or 110 seconds seems like a lot to attribute to a rounding difference but that makes more sense in this example than the lag before the pressure graph starts.
I'll monitor for a while to see if any pattern suggests itself. otherwise, while I don't think it's serious, it might be noted as a potential issue.
RE: time difference between machine and software - GuyScharf - 08-15-2019
Have you compared results with ResScan?