O2 Analyzer without decimal

[BoltSnap]

Changing the conservative factor can have a huge effect, depending on computer. With the older Suunto models you'll be down roughly GF High 55 on consecutive dives if you use the second most liberal setting and have surface intervals that are less than 2 hours.

Much easier to just use the lower O2% and then not go deeper than the MOD of the higher O2%. You could set maximum depth alarm to the shallower depth if you need a reminder.

Suunto computers actually do it for you automatically in the past, they calculate your MOD based on the next higher O2% and calculate your NDL based on a lower O2%. If you are diving 32%, for example, using the next conservatism factor isn't take away much from your dive since you are using NITROX anyways.

I'd do it with Next O2% and next conservatism factor no problem for me BUT in reality it is insignificant. I haven't had to face this issue since my O2 analyzer has more significant figures as so does my DC.

 

[BoltSnap]

Round the FO2 down for NDL calculations and your FO2 up for MOD.

You can only one FO2 value in your dive computer not two.

Your NDL is calculated using integration, MOD is fixed. Shirley no one is using their computer to tell them when they are approaching too high of a PO2? MOD should be part of your dive plan and doesn’t change, NDL can vary widely.

Who are you calling "Shirley"??????




You can use the DC to monitor, control and determine both using a next higher whole O2% and next more conservative setting in your dive computer.

 

[lostsheep]

Don’t be obtuse.

You know exactly what I saying.

You go right on ahead and dive however you want.

 

[berndo]

Hiya
I just bought an O2 analyzer of the brand NRC and realized it only shows full % numbers. We want to use it for teaching the PADI Nitrox course, however the theory specifically states that an analyzer with one decimal should be used. Are there any major concerns for using this and do we need to be more conservative when using it? I do not know if the analyzer already rounds up to the next full number. Any thoughts on this?
Thanks

The reading is accurate enough but what sucks about these basic NRC analyzers is that you can't change the cell. You have to throw away the whole analyzer and get a new one when the cell dies.

 

[Dan G]

Interesting.

My choice (If I had to make this choice) would be just the opposite.

I am thinking in the context of someone asking about a more conservative MOD. We can control our MOD and know what we want it to be despite what is programed into the computer. I round my computer down when FO2 is below xx.5 and up when it is at xx.5 or above.

 

[jale]

The reading is accurate enough but what sucks about these basic NRC analyzers is that you can't change the cell. You have to throw away the whole analyzer and get a new one when the cell dies.

Hi
Not really. You can force open it and change the cell.
Once, I broke the housing and used a small transparent plastic food container to hold the parts...not sexy but it worked
As for the precision, people should not confuse accuracy and precision

 

[Capt Jim Wyatt]

I believe that these O2 analyzers are at best +/- 1% accurate and MAY be only +/- 2% accurate, or somewhere in that range.

For decompression purposes I always use the lowest potential number which causes the dive computer to give a shorter NDL.

For O2 clock purposes I always us the highest potential number when generating tables to determine the oxygen clock limits.

 

[Sevenrider860]

The OP mentions a concern over the analyzer to be used in teaching the PADI Enriched Air Diver course based on this statement from the Instructor Manual.

"A suitable analyzer should read in increments of 0.1% (a tenth of a percent) or less."

I would think any discussion surrounding how one should round the results would be based on the same Instructor Manual guidance.

"Round up or down to the closest whole percent (e.g., round 31.2 percent to 31 percent and 31.8 percent to 32 percent), unless the computer manufacturer literature has a different recommendation."

 

[Sevenrider860]

The more conservative way, from O2 point of view, is to round any number with fraction to the next whole number%. Suunto computers do this in their O2 calculations. If you make 31.4% as 31%, then you are working with lesser O2% in MOD and O2 Tox calculations.

Unless they have changed, Suunto always calculated MOD 1% higher than the O2 percentage entered.

Enter 32% and the Suunto O2 calculations would be based on 33%.

 

[BoltSnap]

Unless they have changed, Suunto always calculated MOD 1% higher than the O2 percentage entered.

Enter 32% and the Suunto O2 calculations would be based on 33%.

Yes, their O2 calculations will be 1% higher but their NDL calculations will be 1% lower.