Perdix (Last deco STOP)

[npole]

The Perdix (AI) set in REC mode doesn't let you change the depth of the last deco stop, it's greyed and defaulted at 3 meters (10 feet), you cannot select 6m.
This is a limitation due to the fact that you cannot change the deco model and the default one requires a mandatory stop at 3m ... or for some other reason?
I feel odd to do a deco stop at 3 meters, and then a (optional) safety stop at 5m ... ?

 

[tbone1004]

the safety stop timer starts as soon as you break 6m in depth and then ticks down. This is "above and beyond" the decompression obligation, just as it is "above and beyond" the requirements for NDL diving. It's a safety stop, if you don't want to do it, don't do it, if you want to do it at 3m instead of 6m, then do it at 3m, the computer doesn't care.

The safety stop does not have to be conducted at 6m, it just has to be conducted between 2m and 6m

The 3m stop does not have to be conducted at 3m, it just means you are able to ascent to 3m if you want to. If you stay at 6m, or wherever, it will calculate in real time what your obligation is. The only difference between the 3m and 6m stops for final stop if you don't want to do the last stop at 3m is that your TTS will be slightly wrong if you aren't decompressing with 100% O2. If you are using 100% O2 as a deco gas, then your TTS doesn't change because offgassing is equally as efficient on 100% O2 at 3m as it is at 6m. If your final gas is anything but 100% O2, then the 3m stop is more efficient to offgas, but it is unlikely that within light recreational bounds that you'll have a difference of more than 2-3 minutes

 

[npole]

The safety stop isn't factored in the deco stop, or I didn't noticed this behavior, with a 2 minutes deco, as soon the 2 minutes reaches zero, the safety timer starts and it is another 5 minutes (it is 5 minutes because I set mine to be dynamic).

But my question is: why in TEC the last stop can be set to 6m while in REC it cannot be changed? It could be just a visual thing... but I don't understand this restriction.

 

[Imla]

I would assume that they would assume that you in rec mode... did rec kinda dives... In other words...

If you want to do deco dives, use the tech mode...
If you want to do rec dives, use the rec mode...

 

[npole]

Excuse me, what's the answer to my question? Why you TEC it's configurable while in REC it is not? The limitation is introduced to? Diving in TEC your body changes?

 

[guruboy]

Because people diving rec don't worry about that kind of thing. That's just the safety stop. Anywhere from 3-6m is fine.

TEC mode just gives you more options if you want them.

 

[npole]

I must live in a strange world then... I do only REC diving and despite the fact that a REC diving should never get any deco, on 90% of my dives i get deco (especially if it's a 2 or 3 tanks dive day).
Changing the mode to TEC, will make unnecessarily complex the info contained in the main screen, with info that I don't really need and with other info that I may use use left out (GTR, mini-3 info display, temperature on the main screen.. etc.).
Should I be considered a "TEC" diver only because I often goes beyond the NDL?

The main problem here however is another, I think I paid enough to have a fully configurable computer (or that what I believed initially), but I'm finding restrictions arbitrary placed here and there with no apparent reason.
We're divers and we're not all identical.. I may be a TEC diver that love to have the the water temperature on the main screen, but yet I've to press a button? Or I may be a REC diver that would have the option to configure its last stop at 6m not 3m in case I hit some deco.

Don't get me wrong, I find the Perdix AI to be the best computer I've ever used and even if I don't need all its features, even the simplest ones are clearly and intuitive, but some decisions seem odd to me. In TEC mode you can turn off the PPO2 in the middle and have a blank spot there, but you cannot add another info you may be interested in? This doesn't make sense, and it's an just an example. Let me fill the whole screen with the clock if I like to do so! It should be me to decide.

I hope one day to have a fully configurable computer with a GUI editor where I can place all the info I want, where I want, in the size I want, in the color I want...

 

[NAM001]

It also assumes alot of things. Rec does not do deco per se. (anly because all dies are deco dives) Rec does not use deco gas's. Rec does not include the training ned to use a lot of the configurations available in tec mode. Why not complain about conservatism being low med and hi in rec and not incrimental GF settings in tec.

 

[tbone1004]

if you have a problem with configurable aspects of the computer, take it up directly with @Shearwater They are very responsive.

putting a name of tec or rec on you as a diver doesn't matter, it's about what information you want on the screen to be available.

I use tec mode for everything. I get
depth-time-stops on the top row
gf99 and @+5 is what I put on there for OC diving in addition to the ppO2 of the gas that I am breathing
bottom row gives me mode, gas I'm set at, and Time to surface

Only thing the rec mode would give me is temp on the screen, but the Shearwater temp sensors are so painfully slow to respond that having it on a second screen is fine. That and most of the time the temp doesn't change that often so to me it isn't really a valuable use of screen space. Mine takes no less than 3 minutes to actually stabilize on the temperature and even then it has always been at least 2*F different than the thermocouple readings when we have placed the probes in the water. It's been my biggest disappointment with my computer.

Shearwater may be nice and give a time/temp setting for the second row in Tec mode which I would actually use when I'm teaching. It'd also nice to have a split cell for PO2 and CNS like they have in rec mode instead of having to put them in two cells

 

[npole]

@KWS: i dive in the real world.. deco is a reality in the real word of many REC divers who doesn't only do those 10m Caribbean reefs (I live in the Mediterrean... if you ask 90% of divers here, deco is basically 100% if you do a 2 tanks day).

Btw yes I can complain with Shearwater and ask them to add "that" option.. but these options are many if you look at it, simply because they didn't freely them from the start. I mean the fields are there, I don't think it would have been so hard to let the user deciding which option to display in every of the X available cell of the main screen keeping them from ALL the available data, adding eventually the option to combine up to 3 values into a single cell, so you can have plenty of data immediately available on the main screen, according to your preference.

Arbitrary limitations in a computer with this price shouldn't exist IMO, and asking me to switch to TEC, when the REC screen suit me better, only to have the possibility to change the deco stop from 3m to 6m sounds "off".