Where Does My Machine Obtain the Time Information

[312capri]

How do our CPAP machines obtain their time of day information? Our "Atomic Clocks" receive their information via the 60KHz transmitter located at the Nation Bureau of Standards in Boulder CO. The NBS uses a cesium beam clock and is the time and frequency standard for our entire country. Do our CPAP machines also synchronize to that time? When I review the information from my SleepyHead software the time stamps seem very accurate.

Just wondering...

[big_dave]

It has an internal clock. The clock on my first machine (acquired used) was off by 1 hr 20 minutes when I bought it. It can be adjusted in the clinician's menu, but this erases all the data (at least on a ResMed machine; I don't know about Respironics machines).

[archangle]

(06-15-2012 04:55 PM)big_dave Wrote:  It has an internal clock. The clock on my first machine (acquired used) was off by 1 hr 20 minutes when I bought it. It can be adjusted in the clinician's menu, but this erases all the data (at least on a ResMed machine; I don't know about Respironics machines).

Respironics machines do not have a way for the user to reset the time, and the clocks do drift over time.

Special cables and proprietary software are required to reset the time on Respironics. Or a way to change the internal battery.

[zonk]

(06-15-2012 04:45 PM)312capri Wrote:  How do our CPAP machines obtain their time of day information? Our "Atomic Clocks" receive their information via the 60KHz transmitter located at the Nation Bureau of Standards in Boulder CO. The NBS uses a cesium beam clock and is the time and frequency standard for our entire country. Do our CPAP machines also synchronize to that time? When I review the information from my SleepyHead software the time stamps seem very accurate.

Just wondering...

Respironics machines don,t have a clock like the S9 which we can change it manually to local time. It does have hidden internal clock set to GMT (Greenwich Mean Time) regardless of local time. You would have put in your time zone so SH can convert to local time

[archangle]

(06-15-2012 05:28 PM)zonk Wrote:  Respironics machines don,t have a clock like the S9 which we can change it manually to local time. It does have hidden internal clock set to GMT (Greenwich Mean Time) regardless of local time. You would have put in your time zone so SH can convert to local time.

Your Windows PC usually knows your local time zone and SH will automatically apply this. I presume the Linux or Mac versions do the same.

[JJJ]

(06-15-2012 09:59 PM)archangle Wrote:  

(06-15-2012 05:28 PM)zonk Wrote:  Respironics machines don,t have a clock like the S9 which we can change it manually to local time. It does have hidden internal clock set to GMT (Greenwich Mean Time) regardless of local time. You would have put in your time zone so SH can convert to local time.

Your Windows PC usually knows your local time zone and SH will automatically apply this. I presume the Linux or Mac versions do the same.

My Philips Respironics System One is 19 minutes fast. That is, if I get up at 6:30 it says I got up at 6:49. It's not a big deal, but I wish I could adjust the time in the machine.

I use SleepyHead on Linux and it reports the time correctly, except for the 19 minute error. The error is in the machine, so there is nothing SleepyHead can do about it.

[archangle]

(06-15-2012 10:47 PM)JJJ Wrote:  I use SleepyHead on Linux and it reports the time correctly, except for the 19 minute error. The error is in the machine, so there is nothing SleepyHead can do about it.

When jedimark makes it back, adding a time correction offset is on his todo list.

Curse you Respironics for not allowing the user to fix the clock or replace the battery.

[cqfd93]

(06-15-2012 10:47 PM)JJJ Wrote:  I use SleepyHead on Linux and it reports the time correctly, except for the 19 minute error. The error is in the machine, so there is nothing SleepyHead can do about it.

Yes, SleepyHead on Ubuntu has a time correction, in Preferences / CPAP / CPAP Clock Drift.

[JJJ]

(06-16-2012 12:53 PM)cqfd93 Wrote:  

(06-15-2012 10:47 PM)JJJ Wrote:  I use SleepyHead on Linux and it reports the time correctly, except for the 19 minute error. The error is in the machine, so there is nothing SleepyHead can do about it.

Yes, SleepyHead on Ubuntu has a time correction, in Preferences / CPAP / CPAP Clock Drift.

Omigod, you're right! I'm using Sleepyhead on Fedora x86_64, but I missed that setting. Thanks for pointing it out!