Nitrox Question

[ianr33]

It IS it is not the computer's responsibility to ensure that the information has been entered correctly.

I agree.

All I ask for is that if I set a computer to,say,32% then the stupid thing remains on that setting until I tell it otherwise!
If I set it to 32%, then dive air the next day, and forget to change the O2 % that's my problem and I deserve to get bent.

I HATE it when technology thinks it's smarter than I am.

 

[Jax]

I agree.

All I ask for is that if I set a computer to,say,32% then the stupid thing remains on that setting until I tell it otherwise!
If I set it to 32%, then dive air the next day, and forget to change the O2 % that's my problem and I deserve to get bent.

I HATE it when technology thinks it's smarter than I am.

Perfect!

 

[Cave Diver]

that's my problem and I deserve to get bent.

I agree. The problem is that too many other people think it's not their problem and ruin things for the rest of us.

Stupid should be painful, not rewarded.

Of course, there's a pretty simple solution that should work for everyone. When you get your nitrox tank, you analyze the contents and once you've done that you set your computer. If you're picking it up from a shop and diving it the next day, then when you verify the contents tag on it, verify your computer setting at the same time.

 

[EastTNDiver]

This has been really interesting and informative, thank you! Like I said, I'm a nitrox newbie and only the divemaster in Tahiti bothered going over everything in detail with me as a quick refresher. I didn't have my nitrox book with me, but I did have my tables and was looking at them while working with my computer.

My dive log shows that the first dive went to 107 feet for 44 minutes. The second dive went down to 93 feet where I saw those readings, and I know I ascended at least 20 feet after seeing the anomalous readings until I got a reading of 1.4. The total dive time was 54 minutes and the last half was coming up a reef so we had an extended safety stop drifting along.

It looks like my computer must have gone into the default mode. After the second dive, the computer read "FO2 50 and PO2 1.90." On the first dive, it read as "FO2 21 and PO2 0.89."

The surface interval was 1 hour, 10 minutes, so it looks like my computer reset into the safety default setting. Now I know to reenter the percentage at each dive.

I don't have an issue with an automatic safety reset, as long as the timeout period is reasonable and it can be turned off. However, unless I'm reading the OP wrong, her unit reset during a repetitive dive SI. If that's the case, I don't see that as "reasonable", and would turn that feature off on that particular computer.

 

[Laurie S.]

Yes, it was a repetitive dive and I didn't expect that the computer would reset that quickly. After diving in Tahiti on nitrox, I noticed that the next day when I dove that it had reset to air. Of course, I noticed that because I went to change the computer to air thinking that it would have stayed at the nitrox setting that it was at last. So now I know to reset each dive, which is a bit of a pain. I saw the default setting and I did set it at off for the first dive. Did it also automatically reset for the second dive? It seems that it did.

I do have the manual for OC-1, but only carry the miniature card that I can't possibly read with the soft contacts I use when diving. I tried to upload the CD with the manual to my laptop and it wouldn't work. I have taken the Sim course through Dive Nav and that helped a great deal. I don't remember there being a nitrox part of that. I'll go back and check it.

 

[String]

I agree.

All I ask for is that if I set a computer to,say,32% then the stupid thing remains on that setting until I tell it otherwise!
If I set it to 32%, then dive air the next day, and forget to change the O2 % that's my problem and I deserve to get bent.

I HATE it when technology thinks it's smarter than I am.

I really don't see the problem with a computer resetting after a fixed surface time. Checking the nitrox mix set is the divers responsibility and it should be done immediately before jumping in as part of their checks.

At least a computer resetting to air is being conservative in terms of nitrogen loading. And if a diver is on nitrox they should be aware of the MoD without relying on a computer to tell them!

 

[DandyDon]

I agree.

All I ask for is that if I set a computer to,say,32% then the stupid thing remains on that setting until I tell it otherwise!
If I set it to 32%, then dive air the next day, and forget to change the O2 % that's my problem and I deserve to get bent.

I HATE it when technology thinks it's smarter than I am.

Yep, I think most Oceanic/Aires dive computer owners turn Default off forever.

Yes, it was a repetitive dive and I didn't expect that the computer would reset that quickly. After diving in Tahiti on nitrox, I noticed that the next day when I dove that it had reset to air. Of course, I noticed that because I went to change the computer to air thinking that it would have stayed at the nitrox setting that it was at last. So now I know to reset each dive, which is a bit of a pain. I saw the default setting and I did set it at off for the first dive. Did it also automatically reset for the second dive? It seems that it did.

If you had Default off, it should have stayed off. Your computer is fancier than any of mine, but that should be the case - unless they changed it. So, did you check your computer? Is it still off?

I do have the manual for OC-1, but only carry the miniature card that I can't possibly read with the soft contacts I use when diving. I tried to upload the CD with the manual to my laptop and it wouldn't work.

I hope you downloaded from the site I linked. If you need additional help, call toll-free: (800) 435-3483. I called so many times over my misunderstanding dive log software for my PC they recognized my voice the next day but they are nice.

BTW, if you ever see your computer show more than 1.6 start ascending. Don't wait for 1.7 or 1.8.

 

[ianr33]

I really don't see the problem with a computer resetting after a fixed surface time. Checking the nitrox mix set is the divers responsibility and it should be done immediately before jumping in as part of their checks.

My main computer these days is a Shearwater,I like that it always displays the gas I have it set to.

IIRC pressing the right button on my Aeris computer brings up the "alternate display" which includes water temperature. IMHO having the O2% there would make much more sense.

And there is always the possibility you check your computer and it resets one second later as you jump into the water. The only way you would know that has happened is the NDLs and pO2 exposure will be wacked.

In the end its not a big deal if you understand your computer. And everyone does that,don't they!

 

[String]

And there is always the possibility you check your computer and it resets one second later as you jump into the water. The only way you would know that has happened is the NDLs and pO2 exposure will be wacked.

Not on any i know, the process of turning them on to check the % resets that clock. I cant think of a single one that puts itself back to air unless its in the off mode. Then again i cant think of a single machine that is unable to tell you the % O2 whilst underwater in a menu somewhere although i will admit im not famliar with the brands that only seem to exist in the USA (oceanic, aeries etc).

 

[ianr33]

Straight from the horses mouth so to speak:


"Summary:
FO2 50% Default ON: computer defaults to 50% O2 / 79% Nitrogen following a Nitrox dive and 10 minutes on the surface. Mix must be set prior to each dive."

http://www.scubaboard.com/forums/2063246-post11.html