Re[2]: Equipment info wrong

[Guido Lerch]

Hi Linus,

I just realized the same, none of my code changes do anything to the events but I am working on a patch to detect pressure drops that happen if you decouple the regulator before the uemis has finished its dive which is usually 2-3 minutes after you surface.

If you have done some fixes already please let me know so we do not duplicate efforts. If you haven't it's a good learning for me but will take some time as I don't know that part of the code yet.

G. Lerch


Montag, 28. September 2015 04:17 +0200 von Linus Torvalds  <torvalds at linux-foundation.org>:
>On Mon, Sep 21, 2015 at 3:30 PM, Guido Lerch < guido.lerch at gmail.com > wrote:
><
>> Has someone recently changed something to the equipment info.
>> Reading a dive from my Uemis today the first time since I test the end
>> pressure in the equipment info is wrong.
>
>I just got the same thing, and my SAC rate was hugely worse than it
>should be, because the end pressure for the dive was recorded as 1.94
>bar, even though the *display* shows 108.05 bar. Small difference
>between tank half full, and tank at ambient pressure.
>
>And it turns out that the pressure reading of 1.94 bar is actually
>technically correct, it's just that the Uemis downloader seems to have
>changed. The end of that dive looks like this:
>
>   ...
>   57:44 2.67m 109.68bar
>   57:47 2.67m 109.57bar
>   57:52 2.58m 109.48bar
>   58:00 2.56m 109.38bar
>   58:03 2.33m 109.24bar
>   58:08 2.37m 109.16bar
>   58:16 2.16m 109.05bar
>   58:19 1.89m 108.96bar
>   58:24 2.09m 108.88bar
>   58:27 2.13m
>   58:32 1.95m 108.78bar
>   58:40 1.57m 108.58bar
>   58:43 1.48m 108.49bar
>   58:48 0.0m
>   ...
>   60:56 0.0m 108.0bar
>   60:59 0.0m 29.5°C 108.02bar
>   61:04 0.0m 108.03bar
>   61:06 0.0m 29.4°C
>   61:12 0.0m 29.5°C
>   61:20 0.0m 108.05bar
>   61:23 0.0m
>   61:28 0.0m 108.06bar cns=4%
>   61:36 0.0m
>   61:39 0.0m
>   61:44 0.0m
>   61:47 0.0m
>   61:52 0.0m 56.11bar
>   62:00 0.0m 29.06bar
>   62:02 0.0m 1.94bar
>   62:08 0.0m
>   62:14 0.0m
>
>ie I came to the *surface with 108 bar, but then a couple of minutes
>later I turned off my air and depressurized the regulator. The Uemis
>has helpfully saved all of that, and while we don't *display* the
>surface events at the end, the "end pressure" calculations and the SAC
>calculations do actually see it.
>
>I *think* the old Uemis downloader used to just ignore pressure events
>at the surface, because I don't recall having seen this before. So I
>suspect it's actually your Uemis changes that caused this.
>
>At the same time, I think we should just ignore the pressure data from
>the surface. It's not meaningful, regardless of whether you
>depressurize the regulator or not, since you'd presumably be breathing
>the surface air, not from the cylinder. So surface time shouldn't
>count towards the SAC, and likewise is meaningless for "end pressure"
>as exemplified above.
>
>So I'll fix the generic code, and we can let the Uemis downloader be.
>
>                Linus
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.subsurface-divelog.org/pipermail/subsurface/attachments/20150928/caed1edd/attachment-0001.html>