IQ-700 NDL Timer?

[Spimon]

Hi,

I have an IQ-700 and yesterday was the first time I used it. It didn't do what I was expecting.

I was expecting it to count down my NDL time, but the entire dive it showed my NDL as 200mins, and remaind the same on my 2nd dive of the day (2hr SI).

Will it only count down over a certain depth (yesterday was max 8.8m), or do I have to follow the dive timer and surface when required, then work out my max 2nd dive time from tables?

I've read the instruction manual but can't find anything to answer my question.

Thanks for any help

- Simon

 

[DA Aquamaster]

The thing that jumps out at me is the shallow max depth of your dive. If the maximum no decompression time remaining for a given depthis 200 minutes or more, all you will see is 200 minutes remaining. For the first or second dive, in plan mode, deeper depths will have lower NDL's.

 

[Spimon]

I see in plan mode it gives the maximum time and I understand for under 10m it's at 200 minutes. However this 200 minutes stayed there for the entire dive.

If I'm at 18m, it gives a max dive time of 47 minutes in plan mode. I'm wondering if once I'm at this depth, will this 47 minutes will count down the longer I'm underwater?

What I'm really interested in is if it give a remaining dive time for multi level dives?

Say I go to 23m for 10 minutes, then up to 16m for 20 minutes, will give me a remaining time based on my dive profile?

 

[ianr33]

What I'm really interested in is if it give a remaining dive time for multi level dives?

Say I go to 23m for 10 minutes, then up to 16m for 20 minutes, will give me a remaining time based on my dive profile?

It certainly should. I used to have one,nice computer.

Do a slightly deeper dive with it to make sure it is operating properly. If the NDL figure does not change with depth and count down during a dive then the computer has a problem.

 

[timle]

I have and use one of these computers. It will show remaining NDL time as the dive progresses. It will (provided it was used) take into account the previous dive and adjust NDL based on residual nitrogen.

My computer will show 200 minutes NDL when I get very shallow. Sounds like you never exceed < 200 minutes NDL yesterday therefore the display never changed. Take it on a dive around 10-12 meters and I expect you will see an NDL < 200 - that counts down. Of course it recalculates as you ascend/descend. So if you got to ~40 meters it may show a very short NDL (probably a few minutes), however if you then ascended to 24 meters that NDL number would increase (multi-level dive).

 

[Spimon]

Thanks guys! I suspected it may need to go beyond 10m to start doing its 'thing'. I'll check it out next time on a deeper dive.

 

[texdiveguy]

I have and use one of these computers. It will show remaining NDL time as the dive progresses. It will (provided it was used) take into account the previous dive and adjust NDL based on residual nitrogen.

My computer will show 200 minutes NDL when I get very shallow. Sounds like you never exceed < 200 minutes NDL yesterday therefore the display never changed. Take it on a dive around 10-12 meters and I expect you will see an NDL < 200 - that counts down. Of course it recalculates as you ascend/descend. So if you got to ~40 meters it may show a very short NDL (probably a few minutes), however if you then ascended to 24 meters that NDL number would increase (multi-level dive).

This is correct.

 

[TUSA]

Hi Spimon-
The follow-up threads are correct. Below is a table representation of the algorithm NDL's for the IQ-700 for your reference, however, the computer will calculate the correct NDL's dependent upon your dive profile.

Depth NDL
9m 200
12m 104
15m 66
18m 47
21m 35
24 25
27 19
30 16
33 14
36 11
39 9
42 8
45 7