Atom2 PO2 alarm comes on early

[adjuster-jd]

I've been using my Atom 2 on several nitrox dives. I have the PO2 alarm set for 1.4. When I get to around 1.2 the alarm starts going off and the display says High PO2. Fortunately I am also using my ProPlus 2 and it says I am ok.
I have double checked the settings for the alarms and it says 1.4. The atom does not register 1.4 it registers 1.2 when the alarm starts.

Anyone have an idea of the cause of this problem?

 

[fppf]

Both the Pro Plus 2 and the Atom have a Warning when you get within .2 ATA of the limit. The Pro Plus 2 just displays the up arrow and the PO2 on the screen, but I don't think it beeps. I have not done a Nitrox dive with the Atom 2.0 yet, I will check back next week and we get back from Cayman.

 

[Divingguy]

Mine did the same thing last week. Both the Atom 2 and VTPro were set for 1.6, but the Atom started giving me a high nitrogen warning. I was VERY glad to have the VT Pro along for cross-reference. I need to compare "conservatism" settings between the two.

 

[Darryl Bowerman]

The Atom 2.0 has an advance warning that is user definable when alarm set points are within a certain amount of minutes. This is in your Set A function menu. Main header will say DTR and default from factory will be 5 minutes. Setting options are from one minute to twenty minutes. I normally set this for zero or one minute remaining. There is a row of little acronyms AIR-TIME-NDC-O2 above the minute set point. So if set at one minute the advance warning alarm will go off one minute before the computer calculates your air time, end dive time, no deco limitation or high PO2 is at the end set point. An option to turn this advance warning off would be to set the unit at zero time.

Regards,
Darryl

 

[adjuster-jd]

This is not a DTR warning but rather a high PO2 warning which I have set to be 1.4 ATA. But I am getting the alarm at 1.2

Well, I read the manual and found that the alarm for PO2 comes on .2 before the set point. I think that's dumb. If I wanted an alarm at 1.2 I would set it for 1.2 not at 1.4!! Now, to suppress the alarm, I need to set the alarm point at 1.6 so that it will alarm at 1.4??? That's just stupid. An alarm point should be just that. I set my depth alarm at 110 feet - it does not start beeping at 100 - it beeps at 110. Same with DTR - If I set it at 5 minutes, it does not beep at 10 minutes.
Who came up with this? Any chance a software revision will be released to correct this issue? I hate to have to *******ize the settings to keep the computer from beeping when it is not supposed to..

The Atom 2.0 has an advance warning that is user definable when alarm set points are within a certain amount of minutes. This is in your Set A function menu. Main header will say DTR and default from factory will be 5 minutes. Setting options are from one minute to twenty minutes. I normally set this for zero or one minute remaining. There is a row of little acronyms AIR-TIME-NDC-O2 above the minute set point. So if set at one minute the advance warning alarm will go off one minute before the computer calculates your air time, end dive time, no deco limitation or high PO2 is at the end set point. An option to turn this advance warning off would be to set the unit at zero time.

Regards,
Darryl

 

[Divingguy]

I agree. This is set up to be almost like a "pre-warning". However, warning beeps and red lights going off at depth, especially when a VT Pro from the same manufacturer is not, is confusing and disconcerting.

 

[Doug Krause]

especially when a VT Pro from the same manufacturer is not, is confusing and disconcerting.

Hi Divingguy,

This is not a true statement. Every nitrox computer that we have ever made, and many other brands operate the same way.

The PO2 limit is considered a critical alarm, as compared to a "reminder" such as the max depth alarm. It is designed to notify you when you approach within .2 ATA of the max PO2 setting. The alarm will sound for 10 seconds, or may be acknowledged and silenced with a 2 second button push. It would then sound again at the actual setting.

Agree or disagree, it is the way that it is designed. I am certainly not one to keep doing things just because that's the way that it's always done. I will add it to my computer develop "wish list" for future consideration.

Doug

 

[Divingguy]

Doug, hang on a second. How can you say that my statement that inconsistency between two Oceanic devices at depth is not confusing or disconcerting "is not a true statement". I certainly thought it was when I was at depth, and was having to try to figure out why my Atom 2 was telling me high nitrogen, ascend, but my VT Pro was giving me no warning whatsoever? Maybe you just had to be there, but you saying that that was not a "true statement" really hit a nerve. I met you at the Scubatoys mask demo. I do not make this stuff up.
Tom

 

[Doug Krause]

I remember meeting - please let me re-phrase. My point is that the computers are designed to do exactly the same thing. So, what we have to determine is why you have experienced something different.

 

[Divingguy]

I am going to try to activate dive mode on both computers this weekend, side by side, and see if there is some difference in settings. Part of the problem may be that since the software configuration for accessing and setting parameters is different between the two units, they may in fact not be exactly the same.
Tom