First Nitrox and computer alarmed

[rustybatey]

I definitely did not confuse the ascent alarm with the toxicity alarm. I have a screenshot of the profile from the software and you can clearly see where the ascent buzzer went off (and it did twice on the ascent but both very brief). You can also clearly see where the buzzer went off and the ascent rate was perfect.

The only thing that i found on the computer was that the ppo2 was set to 1.4 instead of 1.6

I have posted the graphic on a website that I am just starting to work on. Excuse the simplicity

Images ?(Website Under Construction)?

 

[Riger]

I definitely did not confuse the ascent alarm with the toxicity alarm. I have a screenshot of the profile from the software and you can clearly see where the ascent buzzer went off (and it did twice on the ascent but both very brief). You can also clearly see where the buzzer went off and the ascent rate was perfect.

The only thing that i found on the computer was that the ppo2 was set to 1.4 instead of 1.6

I have posted the graphic on a website that I am just starting to work on. Excuse the simplicity

Images ?(Website Under Construction)?

It does look like ascent rate, can you send the logbook file (.slg) to me .. gerstner(at)gmail(dot)com.

I'll have a quick look.

Regards
Richard

 

[Riger]

The only thing that i found on the computer was that the ppo2 was set to 1.4 instead of 1.6

Your PPO₂ settings at 1.4 would have been fine for 32% O₂, you would only hit 1.4 at about 110'.

Regards

Richard

 

[rustybatey]

It does look like ascent rate, can you send the logbook file (.slg) to me .. gerstner(at)gmail(dot)com.

I'll have a quick look.

Regards
Richard

The red area indicates the ascent rate ( 2 small blips on the way up). Where I have the dive marked, the long vertical line, there is no red ascent alert, yet the buzzer is going off (top right corner)

There were at least 4 alarms where it went over 75% O2

take another look

 

[Riger]

I also have a UWATEC, I understand about the alarms being associated with an ascent rate exceeding 100%, and those showing as Red on the profile. On the side of the graph is an image of your computer, and there is a 95% showing there, that is your ascent rate yes?

If you are able to send me the .slg file, I can have a look at it and perhaps give some more valuable comment.

Best Regards
Richard

Regards
Richard

 

[Blackwood]

It's ascent rate.

I just looked at some photos of the Aladin Prime, and there "CNS O2%" flag over that bottom left display if it's referring to CNS (like such: http://www.buvarszakaruhaz.hu/catalog/images/aladin prime.jpg)

I just checked the manual (http://www.dykcen.dk/PDF/Manualer/Uwatec/Manual Aladin Prime Tec UK.pdf), and that computer DOES share those display icons for ascent rate. There is also a "SLOW" flag, but it probably won't lite unless you actually exceed 100%.

My computer (Tec 2G uses the same software). Click on that number and it should cycle between the available displays. I'm betting you'll see CNS% pop up with a much lower value.

edit:

the manual
Optimal ascent rate varies depending on depth between 7 and 20 m/min (23 and 67ft/min). It is displayed as a percent of the reference variable ascent rate. If the ascent rate is greater than 100% of the set value, the black arrow <SLOW> appears.

 

[jviehe]

The Aladdin Prime manual says:

Oxygen toxicity: With the increased
percentage of oxygen, the oxygen in
the tissues (especially in the central
nervous system (CNS)) becomes important.
If the partial pressure of oxygen
rises above 0.5 bar, the CNS O2
value increases, if the partial pressure
of oxygen is below 0.5 bar, the
CNS O2 value decreases. The closer
the CNS O2 value is to 100%, the
closer the limit where symptoms can
occur ->23.

So it would seem that the computer thinks you were exposed to above .5 BAR of 02 long enough to trigger the warning at 75%. If you were below .5 BAR, then it would have lowered the CNS 02%.

 

[Riger]

It's ascent rate.

I just looked at some photos of the Aladin Prime, and there "CNS O2%" flag over that bottom left display if it's referring to CNS (like such: http://www.buvarszakaruhaz.hu/catalog/images/aladin prime.jpg)

I just checked the manual (http://www.dykcen.dk/PDF/Manualer/Uwatec/Manual Aladin Prime Tec UK.pdf), and that computer DOES share those display icons for ascent rate (in % of 30fpm I would guess). There is also a "SLOW" flag, but it probably won't lite unless you actually exceed 100%.

edit:

I agree that the 95% we see on the display is the ascent rate, but that should not be activating the buzzer. The OP is querying why the buzzer/alarm is going off at that time. I think you and I are in agreement that it should not be the CNS because that is still way low on that dive profile.

I am hoping the OP will send me his logfile then I can mess around and compare to my own profiles and see what is causing the alarm perhaps.

Best Regards
Richard

 

[jviehe]

It's ascent rate.

I just looked at some photos of the Aladin Prime, and there "CNS O2%" flag over that bottom left display if it's referring to CNS (like such: http://www.buvarszakaruhaz.hu/catalog/images/aladin prime.jpg)

I just checked the manual (http://www.dykcen.dk/PDF/Manualer/Uwatec/Manual Aladin Prime Tec UK.pdf), and that computer DOES share those display icons for ascent rate. There is also a "SLOW" flag, but it probably won't lite unless you actually exceed 100%.

My computer (Tec 2G uses the same software). Click on that number and it should cycle between the available displays. I'm betting you'll see CNS% pop up with a much lower value.

edit:

Youre probably right. Ive never seen a ascent rate displayed in a percentage.

Optimal ascent rate varies depending on depth between 7 and 20 m/min (23
and 67 ft/min). It is displayed as a percent of the reference variable ascent rate.
If the ascent rate is greater than 100% of the set value, the black arrow
<SLOW> appears. If the ascent rate exceeds 140%, the arrow starts flashing.
Aladin® provides an audible alarm if the ascent rate is 110% or greater. The
intensity of the alarm increases in direct proportion to the degree that the prescribed
ascent rate is exceeded.

 

[Blackwood]

I agree that the 95% we see on the display is the ascent rate, but that should not be activating the buzzer. The OP is querying why the buzzer/alarm is going off at that time. I think you and I are in agreement that it should not be the CNS because that is still way low on that dive profile.

I am hoping the OP will send me his logfile then I can mess around and compare to my own profiles and see what is causing the alarm perhaps.

Best Regards
Richard

He may just be confused as to when it actually buzzed (that first ascent alarm is only a minute or so after the position he's showing in the log).

I agree, though. An exported log would clarify the issue.