Question about the Perdix AI

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And ya, 55m makes for a pretty short dive if you are trying to avoid much deco... :)

There was an accident in Sipadan in Mar this year where the body was found at 55M. When I was diving there last week, I spoke to the DM who pull the body out. He said that the tank was empty.

I've checked the air requirements for the dive based on a RMV of 18. Diving with either two tanks of air, or one of air and one of EAN32 will not allow too much time at 55M.

Since the wheelhouse is at 37M and the main deck is at 45M, there is certainly no need to reach the bottom of the wreck at 55M. We may opt for a longer and shallower dive.
 
That's a big dive and to spend any time at all, and allowing for a decent safety margin, requires some hardware. I'd do it with twin somethings on my back, an 80 of 50% and a 40 of 100%... or something like that anyway... but that's just me. I have a real aversion to running out of gas when I have an hours worth of deco to do... ;-)
 
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I too certainly have an aversion to running out of gas. I don't think they are set up for tec so 50% and 100% may not be available. They may have nitrox tanks but may not have nitrox regulators.

I've checked that 32% at a PPO2 of 1.6 has a MOD of 40M. Perhaps that is why they are suggesting the strange combination of air and 32%. But I don't really want to stray from a PPO2 of 1.6. First time to 55M, I'm keeping the settings conservative. I did say earlier in the thread that I thought the best was to do the dive was with two tanks of air and nitrox in a stage tank. This is not too far from, "twin somethings on my back, an 80 of 50% and a 40 of 100%".
 
I note that the AI allows the choice AI Mini comprising GTR and SAC to be displayed in a single field on the bottom row. If anyone from Shearwater is paying attention, I would welcome the ability to choose the following in a single dispay field:
- GTR and TTS
 
Here is my guess on what is happening. I do not have experience with shearwaters AI model.

My assumptions.

You have multiple pressure sensors. the manual probably says #1 is yours and the others are buddies
The computer is a one tank computer like its predicessors.
The gasses you select is independent of the pressure sensors.
Unless you can assign a sensor to a tank AND A GAS mix you are hosed for what you want to do. It may probably links all gas selections to the #1 sensor.

If the above is true you will have to abandon the AI option when you dive 2 tanks at the same dive.
Your information that is pressure related will be slaved to the #1 sensor for all computations requiring your PSI input.

Ill look at the manual.

My assumptions appear to be wrong about #1 being you. There is a GTR setting that is the committal setting.

I looked at the manual and it is a little fuzzy. Section 5 covers it and the AI says both can be enabled but does not say which is used for computatons. Logic says at that point that the AI selection in non vital and visual information only. However the GTR setting says which is used for computations and I think that is the key.

the AI is informational and not linked to calculations other than sac. the gtr is what links the sensor to your tank and not your buddies the gtr does not allow both to be enabled as I read it.

Another key appears to be that the selections muct be made on the surface so you cant change from one tank to another at depth for calculation purposes 9GTR) but you can =have both AI sensors displayed to view anytime.

If that is true then I would have gtr set to your final used tank and the first tank used monitor on the ai display which you can see both at the same time.

So here is a hypothetiocal.. you are diving doubles with no crossover. you will start on the right tank and finish on the left tank

both tank sensors are enabled. you set the left (final) tank for gtr. You don't care about gtr on the first tank. only the tank that has the only remaning gass for you to use.

Lastly if you have diferent gas mixes in the tanks you will have to change the gass selection when you switch. that gas selection appears to be the only thing you have to change as I read the manual. The only time air related info will be accurate like GTR its ect will be when you are on the last tank. Using different gas in the tanks (MIGHT???) be a formula for hurting your self. It would take more thought on the subject.
 
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It is a 2 transmitter computer.

The gases you select are independant of the transmitters just like the non AI Perdix. All NDL and Deco calculations work on depth and gas selected, which are independant of the amount of gas in the tank which is what the transmitters show.

Don't need to abandon AI for 2 tank dives, can always set 2 transmitters, or 1 transmitter and 1 SPG. Transmitters have to be paired to the computer so the computer ignores non paired transmitters.
 
It is a 2 transmitter computer.

The gases you select are independant of the transmitters just like the non AI Perdix. All NDL and Deco calculations work on depth and gas selected, which are independant of the amount of gas in the tank which is what the transmitters show.

Don't need to abandon AI for 2 tank dives, can always set 2 transmitters, or 1 transmitter and 1 SPG. Transmitters have to be paired to the computer so the computer ignores non paired transmitters.


I am thinking the same but you would want the GTR setting to be the last tank you used so that you had numbers based on the tank gas left and not the first tank you quit using and traded fo rhte full second tank.
 
With 1 transmitter, it clearly states that the AI info relates to T1. With 2 transmitters, I expect they would give information (such as GTR) for both T1 and T2.
 
With 1 transmitter, it clearly states that the AI info relates to T1. With 2 transmitters, I expect they would give information (such as GTR) for both T1 and T2.

What I got was you can monitor both PSI sensors with the ai selection but the GTR can only be off 1 or 2 not both and that what you select will be used calculate the gtr and I assume all psi related computations.
 
https://www.shearwater.com/products/swift/

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