Computer configuration

[ReelDuel]

What alarm/settings do you have/use on you computer? And what do you set them at.
Wet activation=on
ASNT alarm=on
DECO alarm=on
deep alarm=on 130'
Turn Pressure=on 1000psi
End Pressure=on 500psi
PO2=on 1.4 diving (80-100SWF)
RES=on 5 min

sample rate=15 sec

I am just checking to see if I am in the ball park with my settings. I just purchased a DC and new to diving.

Thank you, Fred

 

[Blackwood]

There is no ball park. Those are probably fine, though things like turn pressure may be better viewed as a "per dive" setting (i.e. change it depending on the planned profile).

Also, the turn pressure and end pressure may not be in sync, especially with a 130 floor on what I'm assuming to be single tanks.

I'm not sure what the "PO2=on 1.4 diving (80-100SWF)" setting means. In particular, I'm confused with why a depth range is listed.


The pertinent settings I use are as follows:

Water Activation = On
Gage Mode = On
Sample Rate = 30

 

[ronbeau]

What alarm/settings do you have/use on you computer? And what do you set them at.
Wet activation=on
ASNT alarm=on
DECO alarm=on
deep alarm=on 130'
Turn Pressure=on 1000psi
End Pressure=on 500psi
PO2=on 1.4 diving (80-100SWF)
RES=on 5 min

sample rate=15 sec

I am just checking to see if I am in the ball park with my settings. I just purchased a DC and new to diving.

Thank you, Fred

I agree with Blackwood. I don't understand the depth next to the PO₂ at all. The PO₂ (partial pressure of oxygen) comes into play when diving with Enriched Air (NITROX) which has a higher oxygen content. This will be covered in a NITROX course if you decide you are interested in NITROX diving.

Absent any unusual circumstances for a given dive I usually set the Turn Pressure to 50% of the working pressure of the cylinder I am using. For a 3000 psi aluminum 80 I would set it to 1500 but would I would set it to around 1725 for my HP 100s which have a working pressure of 3442 psi.

The deep alarm should be set on a per dive basis If you expect you maximum depth to be 70 feet you might want to set this to 75 or 80 feet so you will be alerted before you stray too far from your dive plan.

My sampling rate is set to 15.

 

[ReelDuel]

I will check in the morning. I just didn't know all of the alarm features that a DC has. So I have gotten a few wrong. You folks are great. I will look at the DC tomorrow AM and see what the choices are.

Thanks a bunch for the help, Fred

 

[Bubbletrubble]

The PO2 number represents the maximum allowable partial pressure of oxygen exposure. On nitrox-capable dive computers, the user can select how conservative/liberal he wants to make this setting. 1.4 atm is more conservative than 1.6 atm.

The range given (80 - 100SWF) probably represents 80 to 100 salt water feet. (I usually see the units represented as "fsw.") I would expect the range to indicate maximum operating depth (MOD) for a given nitrox mix. According to Wikipedia (Maximum operating depth - Wikipedia, the free encyclopedia), a 39% nitrox mix would give an MOD of 85fsw for 1.4 atm ppO2 and 102fsw for 1.6 atm ppO2. I hope that the manual for your dive computer defines these numbers explicitly. Let us know what you find out.

For now, I would just set the dive computer to "AIR" and not "NITROX." Take a nitrox class to learn how to dive using gas composed of greater than 21% oxygen.

Dive safe.

 

[viceroy]

I agree with Blackwood. I don't understand the depth next to the PO2 at all. The PO2 (partial pressure of oxygen) comes into play when diving with Enriched Air (NITROX) which has a higher oxygen content. This will be covered in a NITROX course if you decide you are interested in NITROX diving.

Actually PO2 plays a role regardless of whether you're diving EAN or not.

It's just that rec diving limits don't come close to 1.4 PO2 when on air

Dive to 54m (1.4 PO2) or 63m or (1.6 PO2) on air and you'd be on the limits of oxygen toxicity

 

[don Francisco]

As others have said there is no one rule of thumb. The computer is a tool & should be set according to how you plan to use it.

Personally, I hate hearing all those alarms going off, especially neat the end of the dive when most of the divers are near the NDL, low on air, out of planned time, ascending too quickly, or all of the above. It sounds like a clock store at noon.

The only alarm I ususaly use is the depth, which I set to either 15 fsw deeper than my planned depth, or 10fsw shallower than the MOD when using Nitrox. Depth is the easiest thing to lose sight of when distracted by or following a creature. By the time I'm nearing other limits, I'm very aware of & tracking my situation, so for me all the other alarms are audio clutter and only tell me what I know already.

 

[Blackwood]

The range given (80 - 100SWF) probably represents 80 to 100 salt water feet.

Clearly... But what's it doing in the settings?

That setting on most dive computers represents a maximum PO₂. It will beep or somehow alert the diver when they reach or near the MOD for whatever gas they've preselected. But MOD isn't a range. It's a single, discreet number.

I can somehow rationalize the 80 as a reference to the shallowest it will beep for a user-specified 1.4 (assuming it's a 'recreational' computer, it won't allow a setting greater than EAN40). But if one is the shallowest limit, the other would logically be the deepest limit, and that doesn't make sense (unless the leanest mixture it recognizes is 35%, but that's highly unlikely).

 

[Meng_Tze]

Actually PO2 plays a role regardless of whether you're diving EAN or not.

It's just that rec diving limits don't come close to 1.4 PO2 when on air

Dive to 54m (1.4 PO2) or 63m or (1.6 PO2) on air and you'd be on the limits of oxygen toxicity

Viceroy is correct in that PO2 plays a role them moment you dive compressed gas with O2 under water.

1.4 was defined by most agencies as the accepted level of PO2 for the working part of the dive. 1.6 is usually used when doing deco.

The only reason I can think of the depth range being part of this, is the ability to set/allow a higher PO2 at a shallower range: for deco? I don't know this computer, but my guess is that you could set/allow 1.5, 1.6 for a shallower range?

Or for deeper dives lower range? 1.0 between 150-200ft? Some people prefer a lower PO2 for deeper/longer dives.

Let us know what the setting possibilities are....

 

[Blackwood]

The only reason I can think of the depth range being part of this, is the ability to set/allow a higher PO2 at a shallower range: for deco? I don't know this computer, but my guess is that you could set/allow 1.5, 1.6 for a shallower range?

I had a similar thought, but dismissed it assuming this to be a single-gas unit.