ATOM NITROX setup problems

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simonc

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Messages
60
Reaction score
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Location
Singapore
# of dives
200 - 499
Hi all,

I recenty bought an ATOM 1.0 r2F firmware.

The dive data mode is setup as follows (SET D group)
F02 GAS1 > AIR
F02 GAS2 > AIR
F02 GAS3 > AIR
F02 50% DEFAULT > ON
RECEIVER > ON
DIG GAUGE > OFF

What does F02 means? More importantly what is F02 50% all about? I can appreciate it only matters when diving NITROX and GAS 1 is a numerical number ie EAN32 not AIR. I just don't understand when the manual says "10 mins on the surface after the recent dive the F02 for GAS 1 will be displayed as 50 and further dives are calculated based on 50% O2 for oxygen and 21% O2 for nitrogen unless the F02 for GAS 1 is set before the dive.

My interpretation is -
Before every dive I need to set the F02 level if FO1 GAS 1 = 21-100 %. This is true only if F02 50% DEFAULT > ON.

Therefore - best to leave F02 50% DEFAULT > OFF. Thay way your EAN settings will remain - you just check the tank before each dive and adjust the F02 level for GAS 1 accordingly.

I am futher confused by the statement regarding the F02 50% DEFAULT > ON "further dives are calculated based on 50% O2 for oxygen and 21% O2 for nitrogen unless the F02 for GAS 1 is set before the dive."

What's the 50% O2 for oxygen and 21% O2 for nitrogen about? Why make reference to both??

Wow......I'm confused.

Thanks,

SimonC
 
One more problem.... My ATOM swaps to Alternate time diplay after 5 mins.... how to I keep it on the main time?

Thanks
 
Hi Simon, I don't have an Atom but what you describe sounds like a fairly common thing (different in the specifics but common in general principle) of the computer defaulting to a non-sensical setting to protect the diver.

As you describe it, if you leave the F02 50% DEFAULT setting to ON, then after 10 minutes into your surface interval have elapsed and you haven't input a new FO2 (which means Fraction 02, e.g. EAN32=FO2 of 32%), then the computer defaults to that safety setting.

Think about what the setting means (or doesn't :)); your computer will use as values in its calculation an oxygen percentage of 50% and a nitrogen percentage of 79%. Clearly, that's wrong. The computer aims to simulate an input error in order to protect from an actual error.

Say for example that you dove 36% on the first dive and 32% the second and the setting on the computer was to keep FO2 constant until you change it (which some people prefer). If the user forgets to manually update the value of FO2, then they could run into obvious problems underwater.

So, in short, this is a mechanism to safeguard the user from his/her own absent-mindedness if the situation arises.
 
simonc:
One more problem.... My ATOM swaps to Alternate time diplay after 5 mins.... how to I keep it on the main time?

Thanks

I've solved this probelm. Hold the select button down for 2 sec.
 
theatis:
Hi Simon, I don't have an Atom but what you describe sounds like a fairly common thing (different in the specifics but common in general principle) of the computer defaulting to a non-sensical setting to protect the diver.

As you describe it, if you leave the F02 50% DEFAULT setting to ON, then after 10 minutes into your surface interval have elapsed and you haven't input a new FO2 (which means Fraction 02, e.g. EAN32=FO2 of 32%), then the computer defaults to that safety setting.

Think about what the setting means (or doesn't :)); your computer will use as values in its calculation an oxygen percentage of 50% and a nitrogen percentage of 79%. Clearly, that's wrong. The computer aims to simulate an input error in order to protect from an actual error.

Say for example that you dove 36% on the first dive and 32% the second and the setting on the computer was to keep FO2 constant until you change it (which some people prefer). If the user forgets to manually update the value of FO2, then they could run into obvious problems underwater.

So, in short, this is a mechanism to safeguard the user from his/her own absent-mindedness if the situation arises.

Thnaks so much.......a great explanation. I'll keep the FO2 50 DEFAULT to ON and make sure I update my FO2 after checking tank FO2 prior to each dive.
 
glad it got worked out.
 
Sir, you should know what "FO2" means from taking your Nitrox class. If you don't know what it means, then you shouldn't be diving nitrox
 
https://www.shearwater.com/products/swift/

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