Perdix (Last deco STOP)

[RayfromTX]

What you are requesting has consequences to anyone that doesn't use what you consider to be important. Switching to default does not solve those consequences.

The goal as I see it was to create a user interface that is easily understandable by anyone likely to use the computer and they have accomplished that so successfully that the computer is purchased by rec divers on that and the quality of the display alone. There is no reason to mess that up just to satisfy a very limited few that want to be able to configure every pixel on the screen. I haven't seen anyone else express agreement that the interface is too limited or lacks important configurability.

It is a technical dive computer and their priorities as evidenced by their product releases have always convinced me that Shearwater has never lost sight of that fact in spite of having the power to let their nerd flag fly.

 

[pinshootr]

so the water temp in Spain changes that rapidly??? even here in the Great Lakes its not changing that much during a dive, WE get cold, colder and frigid!

 

[tbone1004]

@npole

ok, so screen configs aside. let's go back to the safety and deco stops.
Couple questions

1. If you could configure it to a last stop at 6m, why would you? What does it benefit you?
2. Why do you say that you finish your last stop at 3m, then have to descend to 5m for the safety stop?
3. What is stopping you from just completing your deco obligation at 6m?
4. Why do you feel that "rec mode" and "tec mode" define you as a diver? It is just a GUI mode for the computer. The rec mode being a bit less overwhelming than the tec mode for most new divers.

 

[Jack Hammer]

However you shouldn't even ask to me why I would like to see the temperature, you should ask (to yourself?) why a 1000€ computer cannot be set to show the temperature on the main screen in TEC mode. That's the real question.

Perhaps next time you might consider downloading and reading the user manual to see if a dive computer will meet your demanding and specific needs before you spend 1000€ on it.

 

[npole]

1.2.3. Nothing, It was merely the indication.. you know when you like to see all the bits at the right place, I know it's a bit autistic, but I don't like that 3m^ test if I know I will stop at 6.. that's all, nothing that really makes any practical difference;
4. It's not me ! I was joking about the fact that someone who gets any deco is automatically a TEC diver.. ..I'm not, I like the REC main page more, I would like it even more if it was fully customizable.

@pinshootr the thermocline(s) can be repentine, however more than the temperature change, I usually compare what I feel with what can me measured, so I know what's going on with my body and with what's surrounding me.

 

[npole]

Perhaps next time you might consider downloading and reading the user manual to see if a dive computer will meet your demanding and specific needs before you spend 1000€ on it.

Ironically the manual says the opposite without specifying that it wouldn't be available (for whatever reason) in some of the offered modes (Pag.64):

Last Stop Allows you to choose where to do your last stop. The choices are 10ft/3m and 20ft/6m. Note that this setting does not affect decompression. It only makes the TTS prediction more accurate.

With no indication that this option isn't available in REC mode.
Then after you figure that something is wrong, you go on the specific REC manual, and the section relative to the deco setup (Pag.19) completely ignores to mention that the above parameter can be edited only in TEC mode. But at least they got the picture right, since after you have figured the arcane, you will notice that is colored grey.

Yes, I downloaded and read the manual before spending those 1000€ ...and btw I would have spent them anyway (see my previous answer).

 

[tbone1004]

@npole from the recreational nitrox mode manual

Decompression stops occur at fixed 10ft (3m) intervals

Regarding the stops in the manual. On the page you can download 3 manuals.
One states "(This manual only covers AI features)"
Another states "(This manual covers the Recreational Nitrox operating mode in the Perdix)"
And the third states "(This manual covers operating instructions for all other features of the Perdix AI)"

Unsure if english is your native language or not, and maybe it is something that @Shearwater should put in the top of their manual explaining not only which model the manual covers, but also which mode it covers, but from the statement on the download page, you can assume that anything covered in the third manual will not be applicable to AI mode, or Rec Nitrox mode

 

[npole]

@npole from the recreational nitrox mode manual

Decompression stops occur at fixed 10ft (3m) intervals

Regarding the stops in the manual. On the page you can download 3 manuals.
One states "(This manual only covers AI features)"
Another states "(This manual covers the Recreational Nitrox operating mode in the Perdix)"
And the third states "(This manual covers operating instructions for all other features of the Perdix AI)"

Unsure if english is your native language or not, and maybe it is something that @Shearwater should put in the top of their manual explaining not only which model the manual covers, but also which mode it covers, but from the statement on the download page, you can assume that anything covered in the third manual will not be applicable to AI mode, or Rec Nitrox mode

The different manuals covers the specificity (in example the AI part of the Perdix AI .. and so on).
Intervals (plural) and the last stop can be selected by the user, soon you figure that this option is only available in TEC, in no part of the manual (neither the recreational one) it says that this option is disabled in REC mode. In REC the option is there, it doesn't disappear, n but it's greyed out. They could add the: "NOTE: this option can be changed only in TEC mode"; however the main issue isn't about the manual but why they decided to lock it in REC.

 

[tcoen]

Hi All,

I haven't read this thread in its entirety, so I may miss some of the finer details of the discussion.

However, I can address the question of why we decided to lock out the 6m/20ft last stop option in OC Rec mode. The reason is that a 20ft stop depth is often inappropriate when decompressing using a gas with a high fraction of inert gas. For example, common recreational gases such as air and EAN32 are 79% and 68% nitrogen respectively. This leads to inefficient decompression when performing the entire last stop at the deeper depth of 6m/20ft. With these high inert gas fraction mixes, the extra decompression time when performing a 6m/20ft last stop can be +15 to 20 minutes versus a 3m/10ft last stop in realistic scenarios. Note that low (or zero) inert gas fraction mixes don't have this problem with very long stops at 6m/20ft, but using such mixes is typically considered in the range of technical diving.

Further, setting the last stop depth to 3m/10ft does not prevent the diver from performing the last stop at 6m/20 ft (or any other depth such as 4.5m/15ft for that matter). There is no extra penalty imposed for staying at the deeper depth. However, if you stay at the deeper depth, tissue updating is always based on the actual depth, so off-gassing will be slower, and the predicted Stop Time and TTS will countdown slower than real-time. The predicated times are assuming that the diver will be following the prescribed stop depth schedule.

In choosing to lock out the 6m/20ft last stop depth in OC Rec mode, we had to consider the fundamental purpose of the OC Rec mode which is to be a simpler set of displays and options, with less room for mistakes than the technical mode. We felt that locking out this option was consistent with this goal.

We do appreciate these discussions. Hearing this type of feedback is what helps us tune our products to be inline with what divers want. We certainly don't want to unnecessarily frustrate users. However, as with all decisions, there are trade-offs that must be considered and no optimal solution exists for all possible users. In this case, I will add the request (adjustable last stop in OC Rec mode) to our list of suggestions that we evaluate before firmware releases. This will ensure that we at least discuss it again internally.

Best regards,
Tyler Coen
Shearwater Research

 

[stuartv]

@npole, I basically agree with you. The Perdix is great, but definitely not perfect.

I have asked (in various posts here and in email exchanges with Shearwater) for a variety of changes that I think would make my Perdix AI a better computer (for me).

- I would like to be able to set it to show the current Gradient Factor setting on the main (Tec) screen. I would generally only check it once, at the beginning of a dive. But, that is still more useful to me than some of what is shown there. And it is something that I would like to check on every single dive, so being able to have it shown on the main screen would be nice. Seeing it there would have saved me in the past from diving a different setting than what I intended.

- I would like to be able to set it for a Last Stop of 30ft/9m. A pretty common gas that I and my local tech diving buddies use is EAN80. For a lot of our dives, using 80% instead of 100% allows us to do our final deco a little deeper than 20', where we stay out of the surge/chop that is closer to the surface on rough days out in the ocean. It would be nice to have my TTS shown correctly, based on my dive plan.

- Have Gas Time Remaining shown reflect ALL stops that the computer is going to prompt for, whether they are mandatory or optional. My much-less-expensive recreational computer does this.

- Have Gas Time Remaining continue to show even once in deco. It would be okay with me if that was limited to only being shown when there is only 1 gas Enabled. I.e. you are doing a single tank dive, with no gas switches. My much-less-expensive recreational computer supports 3 gases and it does this.

- Support more than just 2 tank pressure transmitters. My much-less-expensive recreational computer supports 3.

- Have a setting for the tank pressure shown such that it displays T1 (transmitter 1) pressure when the first gas in the gas list is Active, T2 (transmitter 2) pressure when the 2nd gas is in the gas list is Active, etc.. Thus, when this setting is chosen, you could have the display just showing 1 tank pressure and it would automatically be showing the pressure of the gas you're actually breathing. I.e. you could perform a gas switch during the dive and not have to do anything else to see the tank pressure of the gas you switched to. My much-less-expensive recreational computer does this.

I don't know about anyone else, but my transmitters generally just stay on their respective 1st stage regs. And, I always use the same 1st stage(s) for back gas and the same 1st stage(s) for deco gases. So, it would only be a 1 time setup issue to have the computer know which transmitter is for my back gas and which is for deco (or my "other" tank in side mount).

The only day-to-day restriction it would add is making sure I actually set the first gas in the computer to be my back gas and the 2nd to my first deco gas, etc.. Which is not an issue, for me. I don't foresee it being a big deal for recreational divers who are only using 1 gas, either. In fact, it OC Rec mode, it seems like it could disallow configuration of more than 1 gas, thus making the whole GTR thing even easier (in OC Rec mode).

All that said, while the Perdix AI could be better (for my use and desires), I am very happy with it.

However, @npole, maybe you should check out the Ratio iX3M. It might do what you want. It even has the option to connect an O2 analyzer accessory directly to the computer for analyzing your tanks.