Aeris Computers and Reverse Profiles.

[ianr33]

I did 2 dives last sunday and the behaviour of my Aeris Atmos Pro was interesting. I have seen it do this before but this was much more extreme.
(Dives were planned on V-Planner and the computer was along for the ride on the second dive)


First dive was to around 100 feet,came up to 80 or so after a while then lots of time above 30 feet. At depth it was nudging the orange,surfaced with one blob into the green. Nothing too crazy.

Surface Interval 1:47

Second dive was a trimix dive (21/25) to 170,planned for 15 minutes bottom time. Average depth was actually around 150. I just left the computer set on air.

Anyway,by the time we got back up to 30 feet the computer was asking for 105 minutes of deco,wheras a more realistic figure (from V-planner) would be something like 20 minutes

So the computer was being HUGELY conservative,which is odd as the aeris algorithm is normally very liberal.

I fully understand that the Atmos Pro is not intended to be used for this type of diving but I would be interested to know where this conservatism comes from. I suspect it is something that Aeris adds in to discourage reverse profiles (especially if they involve deco) rather than something that is in the base algorithm ??

[WV Diver]

Originally Posted by ianr33

I suspect it is something that Aeris adds in to discourage reverse profiles (especially if they involve deco) rather than something that is in the base algorithm ??

I don't know, seems like it would be kind of late to discourage you if you don't know it's going to happen until you get a 105 deco obligation on the screen.

[meesier42]

I don't know what conservatism is built into it, but it can't be much because I really though the pelagic computers have the most liberal algorithm out there. But then again it really isn't designed for tech diving like that and really don't know how it would react to being exposed to conditions like that. Could just be that you overshoot all of the presets and it just kind of "ran home to mommy" and gave you a bunch of deco obligation to be safe.

[DougNR]

Originally Posted by meesier42

Could just be that you overshoot all of the presets and it just kind of "ran home to mommy" and gave you a bunch of deco obligation to be safe.

I'd have to agree with Meesier42 that your profile just blew the computer away! I understand you stated your concurance that you used the computer outside its designed intent - but for those that may not know, the Atmos Pro is nitrox capable but not tri-mix.

Interresting experiment!