Daylight Savings time and the S9

Pugsy · Post by **Pugsy** » Sat Nov 05, 2011 8:45 pm

archangle wrote: Heck, Respironics machines can't be changed from an incorrect time to the correct time unless you have a proprietary cable not available to users and software that Respironics doesn't let the users have.

Yeah, I know. And we can't correct the small number of minutes it loses over time.

I add the part about "generally" because apparently there were some PR S1 machines that did offer GMT offset on the LCD menu screen. Must not have been many but I have a provider manual that lists it. I figured just as sure as I said we couldn't ever change the machine clock then someone would pipe up with the fact that they have a machine that allows for offsetting of GMT on the machine itself.

I can see why some people want it to be perfect but for my needs it doesn't matter when it says I went to bed. I just look at hours asleep anyway.

I figured the Respironics newbies from this summer might be wondering about what to do with their machines when S9 users started the DST discussion again.

idamtnboy · Post by **idamtnboy** » Sat Nov 05, 2011 8:55 pm

Pugsy wrote:I figured the Respironics newbies from this summer might be wondering about what to do with their machines when S9 users started the DST discussion again.

Good thinking. Thanks.

Newbie Woman · Post by **Newbie Woman** » Sat Nov 05, 2011 10:35 pm

I lie to my S9 and set its clock back one hour. When it's 1 pm, S9 thinks it's noon. If I sleep late it doesn't reset itself and put part of my data on the next night's sleep. I had a devil of a time setting back the clock as well as lying about when noon comes. I'm still not sure I did it right. I'll know tomorrow.

P.S. Don't tell anyone I lie to my S9.

NCHawk · Post by **NCHawk** » Sun Nov 06, 2011 10:05 am

When I first got my new machine in February I hadn't been that concerned about checking any of my stats, and only did so occasionally. I did notice that if I didn't check until the afternoon everything was zeroed out except the mask fit indicator; it wasn't until I read it on here that I found out that my CPAP had an actual clock built into it. Since I wasn't trying to check graphs to see what time things happened, I didn't worry about how accurate the clock was.

This morning since I was resetting all the clocks in my house anyway I decided to reset my CPAP too. I noticed that instead of being an hour off, it was a half hour off (it showed 10:50 instead of 10:20). Since I had never verified the time before, I'm not sure if the clock's been off since I got it, or if it's been losing time all along. I've also traveled with it twice, so that may have messed up the time setting.

Slinky · Post by **Slinky** » Sun Nov 06, 2011 10:14 am

Yeah, it really is surprising that these PAPs can't keep accurate time, isn't it? Satellites tell time. But then, come to think of it, my 'puter seems to go off by a few minutes over the course of a couple of months. Goshes! IF I can't trust my 'puter what CAN I trust for accurate time??? No wonder I'm always late. Just you watch. I'll be late for my own funeral too!!!!

kurtamus · Post by **kurtamus** » Wed Nov 09, 2011 10:45 pm

I sure hope you can help me. I was putting my mask on last night and decided I should change the time on my S9 to reflect the recent DST change. I tried to change it back an hour and of course got the "Data Exists" error message.

I came to the forum and did a search and found your post and saw the part about not changing the time between midnite and 1 am, looked at the time and it was 12:40 am! Doh!

I could only set the time ahead 12 hours (or more) any time before that resulted in the "data exists" message. So I set it for 12 hours in the future, in other words it was set for 1 PM when it was 1 AM

I came home from work tonight and was able to set the correct time, but of course my machine now thinks it is Thursday 11/10/11 (tomorrow). If I try to set the date back to 11/09/11 I get the "data exists" message. Arrgh!

If I wait until after midnight (until the date is 11/10) will I be able to set the day back, or do I just have to live with the date being one day ahead? I can't see any way to set the date back without there being data for the date without not using for a night, which I can't do.

I would appreciate any help you can give, I just cant seem to wrap my head around how to get the date set back a day.

Kurt

idamtnboy wrote:Here is what I have tested and am quite sure is safe advice.

There are two windows when you can change the time on the S9 and not get the 'data exists' error message.

1. The time frame beginning something more than one hour after therapy is stopped, i.e., the air generator is turned off, and noon. That window must be longer than one hour. For example, you wake up and turn off the air generator at 7:12 am. You don't need to power it down. You can set the time back one hour anytime between approx 8:15 and noon. Give yourself a few minutes leeway on the one hour after stopping therapy because I don't know just how soon the S9 is finished recording data.

2. Anytime after 1:00 pm and before you turn the blower on. If you accidentally turn the blower on, turn it off and wait more than one hour. You can probably set the clock back then but I haven't confirmed that. The S9 begins recording data as soon as you turn the blower on, and you cannot set the clock back into any time span for which data exists.

Don't try to set the clock back on the S9 between midnight and 1:00 am because that requires you to set the date back one day. The S9 doesn't like to do that because there is data existing for the previous day. And I suggest you don't set it back between noon and 1:00 pm because noon is the changeover from one S9 day to the next, and data in the summary file is split at that time.

Resscan maybe has a problem in the display of data for the day after the time change and may show a gap, or overlapping data, from 2 am to 3 am, Sunday, in flow and detail data. This is based on some problems some users experienced last spring when changing time. The data exists on the card. If you changed the time on your S9 between the last mask session of the night and noon you may have a problem when saving and closing Resscan after downloading. It appears that everyone who changed the time on the S9 between noon and the first mask session of the night had no problem when downloading, saving, and closing Resscan. This was last spring when we set the clocks ahead. I don't know if Resscan will fouled up for the fall time change.

I suggest the best time to reset the clock and avoid any potential problems is after 1:00 pm any day before Sunday, and any day after Sunday.

RandyJ · Post by **RandyJ** » Thu Nov 10, 2011 5:39 am

Kurt,

I am in the same position as you. I think the only solution to set correct date (setting machine back one day) is to perform the "Erase All Data" function. However, if you are still reporting compliance data for insurance, you proabably don't want to do this.

In my case my compliance reporting is finished next month so I am living with the machine being one day in the future until then.

RandyJ

RandyJ · Post by **RandyJ** » Thu Nov 10, 2011 5:44 am

I successfully set the time on my S9 back one hour; the sd card was not in the machine at the time because I had taken it out to read it.

When I put the card in shortly thereafter, the screen displayed "Reading sd card" then "Erasing sd card". Has this happened to anyone?

More importantly, does anyone know if, following an erasure of the card, the machine rewrites compliance (summary) data to the card? Or will I probably have to print this info from ResScan for my DME when they ask me for the card for compliance reading?

archangle · Post by **archangle** » Thu Nov 10, 2011 9:42 pm

RandyJ wrote:I successfully set the time on my S9 back one hour; the sd card was not in the machine at the time because I had taken it out to read it.

When I put the card in shortly thereafter, the screen displayed "Reading sd card" then "Erasing sd card". Has this happened to anyone?

More importantly, does anyone know if, following an erasure of the card, the machine rewrites compliance (summary) data to the card? Or will I probably have to print this info from ResScan for my DME when they ask me for the card for compliance reading?

Geez, that's not just stupid, that's CRIMINAL.

RandyJ · Post by **RandyJ** » Thu Nov 10, 2011 10:10 pm

archangle wrote: Geez, that's not just stupid, that's CRIMINAL.

In what sense?

idamtnboy · Post by **idamtnboy** » Thu Nov 10, 2011 10:31 pm

kurtamus wrote:If I wait until after midnight (until the date is 11/10) will I be able to set the day back, or do I just have to live with the date being one day ahead? I can't see any way to set the date back without there being data for the date without not using for a night, which I can't do.

I would appreciate any help you can give, I just cant seem to wrap my head around how to get the date set back a day.

Kurt

idamtnboy wrote:Don't try to set the clock back on the S9 between midnight and 1:00 am because that requires you to set the date back one day. The S9 doesn't like to do that because there is data existing for the previous day. And I suggest you don't set it back between noon and 1:00 pm because noon is the changeover from one S9 day to the next, and data in the summary file is split at that time.

The only way I know of to set the date back one day is to not use the machine, i.e., don't turn it on, for at least 24 hours, and maybe even 36 hours. But I can't say with any certainty that that will work. I did exactly the same thing last year as you did now. I just bit the bullet and let the machine wipe out the data as I had it on my PC. I was past the compliance period so that wasn't a concern. I have a one day blank in my Resscan file, Nov 6, 2010 although I have a printed copy for that day, dated as Nov 7.

You're caught in a 12 hour window crunch. The Resmed day changes at 12 noon so after 12 noon there is data existing for the time from 12 midnight to 12 noon. The day of course changes at midnight, but you can't change the date back between midnight and noon because the summary data file has already been advanced to cover the previous day. The summary data file always has a record for tomorrow in it, it just doesn't have any data in it. It's a place holder. What I don't know is when the summary data file has tomorrow's record added, whether it happens as long as the machine is powered up but not turned on, or only after the flow generator is turned on. There is no way to edit the summary data file with a hex editor and not have the S9 reject it as being bum data and erasing the card. The S9 has no tolerance for having data being messed with.

From what I know of the data and dates, etc., when it comes to setting the date back one day and keeping all your data, you are pretty much SOL.

idamtnboy · Post by **idamtnboy** » Thu Nov 10, 2011 10:37 pm

RandyJ wrote:I successfully set the time on my S9 back one hour; the sd card was not in the machine at the time because I had taken it out to read it.

When I put the card in shortly thereafter, the screen displayed "Reading sd card" then "Erasing sd card". Has this happened to anyone?

More importantly, does anyone know if, following an erasure of the card, the machine rewrites compliance (summary) data to the card? Or will I probably have to print this info from ResScan for my DME when they ask me for the card for compliance reading?

The summary data is rewritten to the card.

You must have made the time change during one of the no-no periods. Since the S9 didn't see any data other than the summary data in its onboard memory it was happy to accommodate you. As soon as you put the card back in it saw data on the card date and time stamped after the clock time, an absolute no-no. You can't have data exist for a time period that hasn't occurred yet.

The other possibility is your PC wrote something to the card. If anything other than the S9's own pristine data exists on the card, the S9 rejects it. I used a hex editor to recover a flow data file on the SD that had been deleted by the S9 'round robin' recording scheme. The S9 didn't like the taste of the data on the card and spit it all out, i.e., erased the card.

idamtnboy · Post by **idamtnboy** » Thu Nov 10, 2011 10:50 pm

archangle wrote:Geez, that's not just stupid, that's CRIMINAL.

Actually it's not. The S9 has fairly extensive routines in it to GUARANTEE that the data on the SD card came only from that S9. In other words, the system is designed to prevent the crime of falsifying data on the SD card. There is a breakdown in this scheme in the sense that Resscan is more tolerant of data layout on the SD card. It can also be hacked to ignore the CRC file and just swallow the data files from the card. So the integrity of the data going into Resscan is not as fool proof as the data coming out of the S9.

RandyJ · Post by **RandyJ** » Fri Nov 11, 2011 5:31 am

idamtnboy wrote: The summary data is rewritten to the card.

You must have made the time change during one of the no-no periods. Since the S9 didn't see any data other than the summary data in its onboard memory it was happy to accommodate you. As soon as you put the card back in it saw data on the card date and time stamped after the clock time, an absolute no-no. You can't have data exist for a time period that hasn't occurred yet.

The other possibility is your PC wrote something to the card. If anything other than the S9's own pristine data exists on the card, the S9 rejects it. I used a hex editor to recover a flow data file on the SD that had been deleted by the S9 'round robin' recording scheme. The S9 didn't like the taste of the data on the card and spit it all out, i.e., erased the card.

Thank you for explaining all that, it was very helpful.

I always lock my sd card before reading it on PC and unlock it again before re-inserting in S9, so it was entirely because the time had been changed one hour back on the S9. I didn't think it would matter since the card had been out for more than 8 hours and the card itself can't tell time.

squid13 · Post by **squid13** » Fri Nov 11, 2011 2:00 pm

I've noticed when reading threads and where the person is from that a lot of people haven't set there machine time back yet.

Daylight Savings time and the S9

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