Switching gasses with D9

[mikestairs]

Hey Guys, i was on a course doing a deep dive the other day when the instructor had us clip on a 40cuft bottle for safety/practice and i wondered...

i have a D9 with transmitter, and if i switched tanks to one with nitrox for example... how do you account for that with the dive computer?

as the computer has the transmitter on the primary tank, and calculates the remaining air time/psi remaining stuff... would it just go along with the new mix even though it dosen't have the pressure readings?


just read through the manual and it wasen't entirely clear, would the computer recognize a transmitter on the 2nd tank?



looking to get into nitrox diving, and carrying an extra cylinder on deep dives.



any insight would be appreciated.


Thanks, Mike

 

[mikestairs]

Bump, Anyone?

 

[NCadiver]

It does the calculation NDL without taking gas consumption calculation into consideration. It only setup for on transmitter and I don't think you can change modes underwater.

 

[mselenaous]

Great question. I've been trying to figure this out myself.

 

[ajduplessis]

All DC's track gas, depth and time to calculate deco obligations. Gas consumption and cylinder pressure is not relevant and has no baring on NDL/deco calculations. Thus when you switch gasses you make the switch on the DC and it will calculate the new mix, depth and time factors in conjunction with what was previously tracked.

Yes, the D9 can do gas switches. First you need to define the gasses you will use before the dive. This is done the EAN Mode and needs to be “on”. You can only switch the appropriate gas if you are at the correct depth for that gas. Bottom gas PO2 should not be higher than 1.4 and deco 1.6.

The D9 has support for 3 mixes. The D9tx (trimix) support up to 8.


FYI - I don't make use of transmitter during any technical dive and would not recommend it either!!

 

[DuboisP]

Bottom gas PO2 should not be higher than 1.4 and deco 1.6.

it's an opinion, not a rule.

 

[skankpile]

The Cochran Gemini modifies the NDL/Deco stops based on temperature and SAC.. so I know a computer that uses the consumption for the calculations. It also uses the salinity, altitude, loading, and samples at 1sec intervals. If you change cochrans for some reason after a dive you can also copy the loading from one cochran to another, and you can replace the batteries on the boat easily.

My 10yr old daughter uses a Suunto so I cant really say anything bad about it...

 

[ianr33]

The Cochran Gemini modifies the NDL/Deco stops based on temperature and SAC.. so I know a computer that uses the consumption for the calculations. It also uses the salinity, altitude, loading, and samples at 1sec intervals. If you change cochrans for some reason after a dive you can also copy the loading from one cochran to another, and you can replace the batteries on the boat easily.

My 10yr old daughter uses a Suunto so I cant really say anything bad about it...

That's all very interesting.

Does it have anything to do with this thread?

 

[mikestairs]

Cool. Thanks for the replies. 8 gasses for the new D9 eh... Damm.

I figured it was probably the case it disregards the tank readings for the new blend, just wanted to make sure. As I just finished a Divemaster course, and am doing a nitrox class next week! Weeeee!

 

[DuboisP]

Cool. Thanks for the replies. 8 gasses for the new D9 eh... Damm.

I figured it was probably the case it disregards the tank readings for the new blend, just wanted to make sure. As I just finished a Divemaster course, and am doing a nitrox class next week! Weeeee!

the old D9 manages also only one tank.
when you're diving with multiple tanks, it's a very technical dive, so you plan your dive.
you know how much time you stay at a deep, you know how much mix you will use, you know when you switch to another mix, you plan with a secure consumption.
if you dive your plan, you don't need to look at your pressure gauge so, why manage 8 wireless transmitters ?