BAR shows pressure but ATR is 0

[lermontov]

I have a proplus 3 and I've noticed that the Air Tim Remaining is going to 0 when I have about 70 Bar left, I thought it might be a settings issue but cant seem to find anything setting to confirm this, it doesnt seem to make any difference if Im on single tank or twins, I thought it should have some correlation between Pressure reading and Air remaining remaining, even if I ascend to shallower water it says on 0

any ideas?

 

[tursiops]

ATR=0 means you have no time left at whatever depth you are at, and you need to ascend. Your PP3 is set to 70 bars for the End Pressure Alarm, so when you get down to 70 bars, ATR=0. You can change your End Pressure Alarm to 50 bars, for example, then ATR=0 means you have 50 bars left. ATR is not related to your deco status, or O2 status, just your SAC and your depth. Dive Time Remaining, will show the lesser of ATR, time left before you hit your NDL, or time left before you hit an O2 limit. DTR will increase slightly as you go up and release pressure and your NDL increases.

 

[CuzzA]

To eloqborate on what was said. You should calculate what your reserve air or reserve pressure is based on what you AND your buddy would need to safely surface if either one of you had a catastrophic loss of air. Obviously your buddy should do the same for you. This calculator will give you an idea of how to calculate this. DiveNerd - Rock Bottom Calculator, Imperial Units Once you have set the correct reserve pressure your computer will calculate on the fly based on depth and air consumption rate your air time remaining based on your reserve. This means you should be on the surface when your ATR expires.

 

[tursiops]

This means you should be on the surface when your ATR expires.

ATR expiring means you have no time left at whatever depth you are at. You still have your full reserve that you have set, 70 bar in the OP's case.

 

[lermontov]

To eloqborate on what was said. You should calculate what your reserve air or reserve pressure is based on what you AND your buddy would need to safely surface if either one of you had a catastrophic loss of air. Obviously your buddy should do the same for you. This calculator will give you an idea of how to calculate this. DiveNerd - Rock Bottom Calculator, Imperial Units Once you have set the correct reserve pressure your computer will calculate on the fly based on depth and air consumption rate your air time remaining based on your reserve. This means you should be on the surface when your ATR expires.

thanks I've checked my settings and the turn pressure alarm is set to 100 and end pressure set to 55, even so if I'm on twins and I'm showing 70 Bar its 140 Bar if I'm on single, so plenty of air, (although the computer doesn't know I'm on twins i guess)

 

[Kairoos]

I think I can help you here. I have an Oceanic VT4.1 so ATR should work the same in your computer as it does in mine. This is from the Oceanic manual for the VT4.1:

ATR is the time you can remain at the present Depth and still safely surface with the Tank Pressure reserve that you selected during setup (End Pressure Alarm Setting).​

So whatever value you set for your end pressure alarm setting will be the value that your computer calculates for your ATR. So with the end pressure set to 55 when you have 70 bar with 0 ATR it's saying you need to end your dive now if you want to surface with the amount of air you set for the end pressure alarm.

I have my end pressure alarm setting set at like 600 or 700 PSI because that's how much I would like to surface with.

 

[lermontov]

I think I can help you here. I have an Oceanic VT4.1 so ATR should work the same in your computer as it does in mine. This is from the Oceanic manual for the VT4.1:

ATR is the time you can remain at the present Depth and still safely surface with the Tank Pressure reserve that you selected during setup (End Pressure Alarm Setting).​

So whatever value you set for your end pressure alarm setting will be the value that your computer calculates for your ATR. So with the end pressure set to 55 when you have 70 bar with 0 ATR it's saying you need to end your dive now if you want to surface with the amount of air you set for the end pressure alarm.

I have my end pressure alarm setting set at like 600 or 700 PSI because that's how much I would like to surface with.

great- yes ok that makes sense

 

[CuzzA]

ATR expiring means you have no time left at whatever depth you are at. You still have your full reserve that you have set, 70 bar in the OP's case.

Right. But again you should be on the surface when you've reached your reserve, which would correlate with your ATR expiring. I don't believe it's a good practice to begin your ascent when you have reached your reserve. You should be on the surface with your reserve. It's your backup parachute for lack of a better term. Sticking with the sky diving metaphor... You wouldn't hop back on the plane after your first jump to deploy your backup on a shorter jump.

 

[Bob DBF]

I don't believe it's a good practice to begin your ascent when you have reached your reserve. You should be on the surface with your reserve.

ATR is the time you can remain at the present Depth and still safely surface with the Tank Pressure reserve that you selected during setup (End Pressure Alarm Setting).

Sounds to me like it calculates the air you need to surface so you hit the surface with the reserve pressure you selected.


Bob

 

[Kairoos]

Sounds to me like it calculates the air you need to surface so you hit the surface with the reserve pressure you selected.


Bob

Exactly.