CNS 97%
CNS 97%
Why does the computer suddenly calculate that the CNS value increases from 3% to 97% for a 9m dive on air. Lenght of the dive was 66 minutes. Yes, the data in the computer seems to be not correct for that either. Look at the attached file.
Is this a faulty sensor? Some other problem? Does this happen often for the members of this forum?
Meaning you cannot trust the calculations from this dive computer?
Re: CNS 97%
Hum, this never happened to me (about 1000 dives with an OSTC).
Kind regards.
Kind regards.
Didier A. Defay
OC trimix instructor / Trimix CCR diver
France
OSTC 2 #18835
- OSTC Plus #16077
-- OSTC 3+ #4806
--- OSTC 3 #3999
OC trimix instructor / Trimix CCR diver
France
OSTC 2 #18835
- OSTC Plus #16077
-- OSTC 3+ #4806
--- OSTC 3 #3999
Re: CNS 97%
What gas was the dive on, i.e. what gas was selected on the OSTC?
Can you post a screenshot from the dive profile from the logbook?
Can you post a screenshot from the dive profile from the logbook?
Re: CNS 97%
I had selected air. I cannot show the dive profile, cause of an internal error. That I can show. meaning that I can show that the computer cannot show the dive profile. I wonder why If this bug has happened once, it can happen twice or trice or...many times.
Re: CNS 97%
OK, that makes it harder to tell what happened...
When the logbook itself (list of dives, time & depth per dive, CNS before & after, batt level, ...) is avail, put not the profile, thisis most likely that the profile storage is full and new dives overwrite the oldest ones. That because the statistical data have fixed size and one can pompute now many dives can be stored before the oldest one gets overwritten. The profile data go into a separate storage space and the amount of memory used for a dive depends on the length of the dive and how many parameters are recorded (e.g. CCR mode produces more data than OC). So both memory areas start overwriting (replacing) oldest dives at different times.
What i was after, is to see which gas was selected on that dive. Going up to 97% CNS on such shallow depth smells like (accidentially) O2 (or a very rich Nitrox) was selected. Anyhow, the calculation works, has been proven on thousands of dives done with the code. The calculation is also full independent of any logbook issues that may exist, as during dive mode, logbook is write-only, no data from the logbook go into any part of teh dive calculations.
Maybe there is a pressure sensor issue and the OSTC stayed in dive mode, clocking up CNS %. There are many possibilities, so i can only recomment to go though all settings and check them. Ah, and i assume the was no battery issue during the dive (batt drained), as this may corrupt data.
When the logbook itself (list of dives, time & depth per dive, CNS before & after, batt level, ...) is avail, put not the profile, thisis most likely that the profile storage is full and new dives overwrite the oldest ones. That because the statistical data have fixed size and one can pompute now many dives can be stored before the oldest one gets overwritten. The profile data go into a separate storage space and the amount of memory used for a dive depends on the length of the dive and how many parameters are recorded (e.g. CCR mode produces more data than OC). So both memory areas start overwriting (replacing) oldest dives at different times.
What i was after, is to see which gas was selected on that dive. Going up to 97% CNS on such shallow depth smells like (accidentially) O2 (or a very rich Nitrox) was selected. Anyhow, the calculation works, has been proven on thousands of dives done with the code. The calculation is also full independent of any logbook issues that may exist, as during dive mode, logbook is write-only, no data from the logbook go into any part of teh dive calculations.
Maybe there is a pressure sensor issue and the OSTC stayed in dive mode, clocking up CNS %. There are many possibilities, so i can only recomment to go though all settings and check them. Ah, and i assume the was no battery issue during the dive (batt drained), as this may corrupt data.
Re: CNS 97%
Yes, Ralph, very hard to understand what has happened. And Mr Heinrich and Mr Weikamp is not helping either.
I did not select anything else than air, if oxygen was selected, then the computer did that by itself. Or I smashed the computer to something by accident.
> that the profile storage is full and new dives overwrite the oldest ones.
Yes, one would think so, but in this case the newest dive was not recorded. Then, some but prohibited the computer to erase the oldest block in the flash. According to Heinrich, there are no bugs, I do not believe that.
> What i was after, is to see which gas was selected on that dive.
If possible, if one can dump the raw data from the computer, would heirichsweikamp.com be able to analyze that?
I did not select anything else than air, if oxygen was selected, then the computer did that by itself. Or I smashed the computer to something by accident.
> that the profile storage is full and new dives overwrite the oldest ones.
Yes, one would think so, but in this case the newest dive was not recorded. Then, some but prohibited the computer to erase the oldest block in the flash. According to Heinrich, there are no bugs, I do not believe that.
> What i was after, is to see which gas was selected on that dive.
If possible, if one can dump the raw data from the computer, would heirichsweikamp.com be able to analyze that?
Re: CNS 97%
I have check a couple of abvious settings, nothing has changed, and air is still selected as gas.Ralph wrote: ↑Tuesday 12. November 2024, 06:59 OK, that makes it harder to tell what happened...
Maybe there is a pressure sensor issue and the OSTC stayed in dive mode, clocking up CNS %. There are many possibilities, so i can only recomment to go though all settings and check them. Ah, and i assume the was no battery issue during the dive (batt drained), as this may corrupt data.
Re: CNS 97%
Well then, honestly, give the computer a full reset (Erase Logbook, Tissues and then Reboot). Maybe your unit captured a neutrino (= once in a billon bit flip somethwere in RAM), i don't know.