Problems with gases on Shearwater

Long, Martin martin at
Thu Dec 6 07:51:53 PST 2018

Hi Jef

Looking back through my git history it looks like it may have actually been
imported correctly, so I now suspect that the first issue may not actually
be download issue.  I'll see if I can reproduce that one. It looks like it
happened when added the dives to a trip, and renumbered them.

The second problem, however, is not so much a bug as a challenge. How to
map transmitter data to gasses.

I'll keep you posted



On Thu, 6 Dec 2018 at 15:42, Jef Driesen <jef at> wrote:

> On 2018-12-05 17:17, Long, Martin wrote:
> > I've noticed some problems with the import of gases on Shearwater
> > computers. There are possible 2 issues here, but these seem to be
> > related.
> >
> > 1) I just imported 4 dives from last weekend, all CCR. The first 3
> > were on 13/60 diluent and the last one on 15/57. However, it put all
> > of the divers in as 15/57, which seems to just be the last diluent
> > set. The Shearwater cloud software does identify the correct gas used
> > at the start of the dive.
> >
> > 2) I'm using two transmitters on a Perdix AI. Transmitter 1 is on my
> > diluent, and transmitter 2 on my oxygen. On import it seems to
> > correctly associate my transmitter one with the diluent (apart from
> > the error in 1 above). Now, providing I don't do any gas switches
> > (e.g. a bailout) then transmitter 2 I can simply set up as 100% O2.
> > However, if I do a gas switch, the software automatically assigns this
> > gas switch to cyl 2, and so it becomes associated with the transmitter
> > data.
> >
> > I now have 2 choices... Either I can enter a new gas of 100% and
> > manually type the start and end pressure - however I cannot remote it
> > from cyl 2. Or, I can set cyl 2 as 100%, and add a new one for my
> > baiout gas. However this then means the cylinder swtich then points at
> > the wrong gas, and will say I switched to 100% on my bailout!
> >
> > I don't have a solution to this. As the import process has no manual
> > intervention, it would be tricky to have a solution which works. My
> > suggestion would be to treat transmitters and gas swtiches as
> > completely separate cylinders, and then allow the user to "merge" them
> > later. The current assumption that transmitter 1 will be the first
> > gas, and transmitter 2 will be the next one is incorrect.
> >
> > By the way, the ability to merge the 2 profiles from my Petrel
> > controller, and Perdix backup (with AI) is excellent! and works really
> > well.
> Can you send us the subsurface and libdivecomputer logfiles of a (full)
> download? That will allow us to have a look at the raw data, and see
> where or what is going wrong.
> PS: The shearwater protocol doesn't support memory dumps, but I can
> extract the raw dive data from the download log.
> Jef
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