CNS% ?

[Smiler1968]

Hi,

If I run a simulation on the OSTC 2N to 41m for 48min using Nitrox 24% set to 0, 50% set to 20m and 74% set to 10m on GF 30/85. I get the following.

24 - 2'
21 - 3'
18 - 3'
15 - 4'
12 - 5'
9 - 7'
6 - 10'
3 - 19'
TTS 59' (add the bottom time and it gives 100')
CNS 33%

Now OSTC Planner gives a very similar plan with TTS 59' run time of 99' and CNS at 33%

Now my Baltic Planner gives

27 - 0.54
24 - 1'
21 - 1'
18 - 2'
15 - 4'
12 - 4'
9 - 6'
6 - 6'
4 - 20'
deco time 47'
run time 87'
CNS 47%

As a matter of interest V-Planner gives
27 - 0.54'
24 - 1'
21 - 2'
18 - 3'
15 - 4'
12 - 6'
9 - 6'
6 - 4'
4.5 - 22'
Run time 92'
CNS 50%

Now I know there will be differences when using different planners. However, the OSTC seems to give a slightly longer run time (I've no problems with that by the way) but shows a considerably lower CNS%. Anyone know why?

Regards

Jerry

[swissdiving]

Easy, different models give different times. You can finde plenty of information on the net about the different models. As a matter of fact your question has been discussed several times in this forum so if you do a search you should find the relevant information.

[Smiler1968]

I will give the search function a try. However, I just ran the plan as a dive and it finished with a CNS of 50%. That appears to be in line with the other planners and would suggest there is a problem with the OSTC planner.

I thought maybe the 33% was just for the ascent/deco phase but the bottom time gave me a CNS of about 28%. That added to the 33% would give me over 60%.

Something doesn't add up.

Jerry

I just did a quick search for CNS but couldn't find anything specific.....

[swissdiving]

Try vpm.

[Smiler1968]

Thanks, I tried VPM in the search function but did not find anything that would explain why the CNS readings for the simulated planner would be different to the simulated dive. Am I missing something?

Regards

Jerry

[Smiler1968]

Hello Matthias,

Are you able to say whether the CNS calculation on the planner is working correctly? Or does it just calculate the bottom time or the
Ascent time?

Regards

Jerry

[swissdiving]

Jerry, if u are talking about the OSTC planner you may not get an answer here cause its not a HW software.

The algorythms are the same though.

[heinrichsweikamp]

Hi,

There seems to be an issue in the planer when CF54 is set. Time for a new beta here...

regards,
Matthias

[Smiler1968]

CF54 is the reversal of the deco plan (if I remember correctly)but I've not got that set. The issue that I had was the CNS total for the simulated plan was 33% but when I ran it as a dive it came out at 50%. I was trying to discover whether the planner gives a total CNS for the whole dive or whether there was a bug/issue.

Regards

Jerry

[Solodiver]

your run tables does not show gas switches, you are sure they are all included and done on the same depth?

[Smiler1968]

Solodiver Wrote:
-------------------------------------------------------
> your run tables does not show gas switches, you
> are sure they are all included and done on the
> same depth?


Hi,

I'm not sure which tables you are referring to. I only used the Vplanner and Baltic to get an idea of the CNS% (they just happened to give slightly shorter run times but more CNS% and that started me thinking)

I used the Non HW OSTC Planner to get a plan and a CNS(33%). I then used the OSTC itself to plan the same dive parameters and that gave a very similar plan (as it would if it uses the same algorithms). I then ran the dive on the OSTC (not linked to the planner) and changed gases as and when I should. The Dive itself gave a CNS% of 50 (what I would have expected). There may have been a slight difference in my ascent rate to that of the plan but other than that I stuck to the plan.

Regards

Jerry

[Smiler1968]

Hi, can anyone out there explain to me why there is a difference between the simulated CNS% having calculated the deco commitment and a simulated dive?

Regards

Jerry

[swissdiving]

Jerry

Why don't you contact JD directly. Go to the OSTC Planner website and send him an eMail with your question.

[Smiler1968]

I'm not talking about the non HW planner by JD. I'm talking about the simulator on the OSTC.

Cheers

Jerry

[swissdiving]

Ohhh sorry

[Solodiver]

Smiler1968 Wrote:
> I'm not sure which tables you are referring to.

??? I'm refering to the tables posted by you in the 1st post!? If you would visualize the gas switches in there I'd be happy to re check with my tools also. Then we could also be sure that everyone is speaking about the same...

[Smiler1968]

Solodiver Wrote:
-------------------------------------------------------
> Smiler1968 Wrote:
> > I'm not sure which tables you are referring to.
>
> ??? I'm refering to the tables posted by you in
> the 1st post!? If you would visualize the gas
> switches in there I'd be happy to re check with my
> tools also. Then we could also be sure that
> everyone is speaking about the same...
Hi,

I'm sorry but I seem to have confused matters right from the start. The plans were made with the 50% switched at 20m and the 74% switched at 10. I cant now remember whether there was a swap at 20m & 10m or whether i waited until the 18m & 9m stops. Not that it would make a great deal of difference anyway. I made reference to the other planners only in order to set the scene if you will. It was never my intention to try to compare the different planners/algorithms. I used them to support my statement that something seems to be wrong, somewhere, with the CNS totals.

Forgetting all of the planners. I am trying establish whether the CNS is calculated for the whole of the dive (on the OSTC simulator). The reason I am questioning this is that the simulated deco plan gives a CNS is around 20%. BUT when I simulate it as a dive I get a CNS of around 50% and that is what I would expect.

Regards

Jerry

[swissdiving]

Jerry,

I still don't understand.
You say: "...the simulated deco plan gives a CNS is around 20%"

ahhhh....

Now I think I know what you are talking about.

If you Calculate the Deco on the 2N you get 20%
and if you run the dive on the 2N you get 50%

Is that what you are talking about.

[Smiler1968]

swissdiving Wrote:
-------------------------------------------------------
> Jerry,
>
> I still don't understand.
> You say: "...the simulated deco plan gives a CNS
> is around 20%"
>
> ahhhh....
>
> Now I think I know what you are talking about.
>
> If you Calculate the Deco on the 2N you get 20%
> and if you run the dive on the 2N you get 50%
>
> Is that what you are talking about.

Yes that's exactly what I'm saying (although I meant to say 33% and not 20%);)

Regards

Jerry

[swissdiving]

I'll hazzard a guess, there may be a difference how the 2N calculates the deco stops as opposed to simulating the dive.

I guess Matthias would be able to tell us what the difference is between calculating deco and simulating a dive.

Hey what about JD!? Haven't heard anything from him at all for ages!

[heinrichsweikamp]

Hi,

The deco planer in the OSTC uses the same routine then the normal dive mode. You have a few simplifications with the planer:
- infinite descent speed
- 10m/min ascend speed + 1min between 3m and 0m
- Simulated dives controlled via a PC software (Divinglog, Jdivelog) always use 1000mbar surface pressure

Regards,
Matthias

[Stephan Z]

Hi @all,

i've mentioned this confusion as well and i do not understand this issue as well.
i'm comparing runtimes created by v-planner, j-divelog and ostc 2n with the following parameters:

asc:8m/min, dsc:16m/min
amv bottom: 20l/min, amv deko: 17l/min
Alg. v-planner VPM-B GF90, jdivelog GF10/90, OSTC 2N:L16-GF OC 15/95
Using the common gases 18/45 (60m), NX50 (@21m), Oxy (@6m)

Runtime: 31min @ 60m

here the resulting RTs:
v-planner:
depth stop RT
60m -3
60m 27:15 -31
39m -33
39m 00:22 -34
36m 01:00 -35
33m 01:00 -36
30m 02:00 -38
27m 02:00 -40
24m 02:00 -42
21m 03:00 -45
18m 02:00 -47
15m 04:00 -51
12m 05:00 -56
9m 07:00 -63
6m 09:00 -72
3m 19:00 -91
-91


OTU's Tauchgang: 117
CNS Total: 49,80%

jdivelog
depth stop RT
60 03:45 4
60 27:15 31
39 02:37 34
39 00:22 34
36 01:00 35
33 01:00 36
30 02:00 38
27 02:00 40
24 03:00 43
21 02:00 45
18 03:00 48
15 03:00 51
12 05:00 56
9 08:00 64
6 09:00 73
3 18:00 91


Sauerstoffbelastung -
CNS: 61%
OTUs: 113


OSTC 2N (Simulation on the dive computer)
60
60
39
39 1
36 1
33 1
30 2
27 2
24 4
21 2
18 3
15 3
12 6
9 9
6 10
3 19

CNS 66%

As far as i've understood the procedure the CNS depends on partial presure and residence time. But these resulting CNS do not represent the marginal diffreces in the Runtime.
The OTUs are also diffrent, but the regarding the delta of 0,4% of the maximum of 850 per day i will ignore it this time.

Does anyone have any suggestions where this gap of 16,2 CNS% comes from?

Regards,
Stephan

[Bardass]

ok i will try to explain.
I can't use V-planner, sorry.

Decoplan with Jdivelog
MV-Plan 1.5
Configuration : GF=10-90 PpH2O=0.627 mem
===================================================
DESC: 60m for 03:45 [ 4] on TX 18/45, SP: 0,0, END: 23m
DIVE: 60m for 27:15 [ 31] on TX 18/45, SP: 0,0, END: 23m
ASC : 39m for 02:37 [ 34] on TX 18/45, SP: 0,0, END: 13m
DECO: 39m for 00:22 [ 34] on TX 18/45, SP: 0,0, END: 13m M-Value: 65% [02], GF: 16%
DECO: 36m for 01:00 [ 35] on TX 18/45, SP: 0,0, END: 12m M-Value: 68% [03], GF: 22%
DECO: 33m for 01:00 [ 36] on TX 18/45, SP: 0,0, END: 10m M-Value: 71% [03], GF: 28%
DECO: 30m for 02:00 [ 38] on TX 18/45, SP: 0,0, END: 9m M-Value: 74% [04], GF: 35%
DECO: 27m for 02:00 [ 40] on TX 18/45, SP: 0,0, END: 7m M-Value: 76% [04], GF: 41%
DECO: 24m for 03:00 [ 43] on TX 18/45, SP: 0,0, END: 6m M-Value: 79% [04], GF: 47%
DECO: 21m for 02:00 [ 45] on NX 50, SP: 0,0, END: 10m M-Value: 81% [05], GF: 53%
DECO: 18m for 03:00 [ 48] on NX 50, SP: 0,0, END: 8m M-Value: 83% [05], GF: 59%
DECO: 15m for 03:00 [ 51] on NX 50, SP: 0,0, END: 6m M-Value: 84% [06], GF: 65%
DECO: 12m for 05:00 [ 56] on NX 50, SP: 0,0, END: 4m M-Value: 88% [06], GF: 72%
DECO: 9m for 08:00 [ 64] on NX 50, SP: 0,0, END: 2m M-Value: 90% [07], GF: 78%
DECO: 6m for 09:00 [ 73] on Oxy 100, SP: 0,0, END: 0m M-Value: 92% [08], GF: 84%
DECO: 3m for 18:00 [ 91] on Oxy 100, SP: 0,0, END: 0m M-Value: 94% [08], GF: 90%

Consommation de gaz basée sur VRM Plongée =20.0, VRM Déco =17.0L/min
TX 18/45 : 5045.1L
NX 50 : 821.1L
Oxy 100 : 642.6L
Toxicité oxygène - OTUs : 113 SNC : 61%



Decoplan with OSTC Planner with Patm = 1013 mbar

Modèle Bühlmann ZH-L16C-1a 2002 modifié GRADIENT FACTOR:
* GF_low (CF32) = 15 %
* GF_high (CF33) = 95 %
* marge de palier (CF16) = 1.0 m
* dernier palier (CF29) = 3 m
* début de plongée à Pamb = 1013 mbar
Gas#1 = 18/45 at 0 m
Gas#2 = 50/0 at 21 m
Gas#3 = 100/0 at 6 m
Durée de changement de gaz (CF55) = 1 min

0:00 60.0m DESCENT DONE
...
31:04 60.0m Déco:
36 m : 1 ' 34 '
33 m : 1 ' 36 '
30 m : 2 ' 38 '
27 m : 2 ' 40 '
24 m : 3 ' 44 '
21 m : 2 ' 46 ' (GAS SWITCH)
18 m : 3 ' 49 '
15 m : 3 ' 53 '
12 m : 6 ' 59 '
9 m : 8 ' 67 '
6 m : 9 ' 76 ' (GAS SWITCH)
3 m : 19 ' 96 '
0 m : --- ' 97 '
DTR = 66 '
SNC = 63%


Same dive with Patm = 991 mbar (my home)

Modèle Bühlmann ZH-L16C-1a 2002 modifié GRADIENT FACTOR:
* GF_low (CF32) = 15 %
* GF_high (CF33) = 95 %
* marge de palier (CF16) = 1.0 m
* dernier palier (CF29) = 3 m
* début de plongée à Pamb = 991 mbar
Gas#1 = 18/45 at 0 m
Gas#2 = 50/0 at 21 m
Gas#3 = 100/0 at 6 m
Durée de changement de gaz (CF55) = 1 min

0:00 60.0m DESCENT DONE
...
31:00 60.0m Déco:
36 m : 1 ' 34 '
33 m : 1 ' 36 '
30 m : 2 ' 38 '
27 m : 2 ' 40 '
24 m : 3 ' 44 '
21 m : 2 ' 46 ' (GAS SWITCH)
18 m : 3 ' 49 '
15 m : 3 ' 52 '
12 m : 6 ' 59 '
9 m : 8 ' 67 '
6 m : 10 ' 77 ' (GAS SWITCH)
3 m : 18 ' 96 '
0 m : --- ' 96 '
DTR = 66 '
SNC = 60%


SNC are almost the same with Jdivelog, it only depends on surface pressure.

And don't forget what Matthias said about descent speed : with ostc simulator, descent speed is infinite.
With Jdivelog and V-planner, you stay only 27' at 60m
with OSTC, you stay 31' at 60m. That's why OSTC calculcate a bigger value for SNC.

If you stay 27' at 60m with OSTC, SNC = 51%, almost same value than V-planner.

[Bardass]

More ...
Jdivelog use Mv-Plan 1.5 with ZHL16 version B

SNC = 61%

If you use MV-Plan 1.5.2 with ZHL16 version C (same as OSTC)

MV-Plan 1.5.2
Configuration : GF=10-90 Factors:1.0/1.0 PpH2O=0.627 mem ZHL16C
=========================================================
DESC: 60m for 03:45 [ 4] on Trimix 18/45, SP: 0,0, END: 23m
DIVE: 60m for 27:15 [ 31] on Trimix 18/45, SP: 0,0, END: 23m
ASC : 39m for 02:37 [ 34] on Trimix 18/45, SP: 0,0, END: 13m
DECO: 39m for 00:22 [ 34] on Trimix 18/45, SP: 0,0, END: 13m M-Value: 65% [02], GF: 16%
DECO: 36m for 01:00 [ 35] on Trimix 18/45, SP: 0,0, END: 12m M-Value: 68% [03], GF: 22%
DECO: 33m for 01:00 [ 36] on Trimix 18/45, SP: 0,0, END: 10m M-Value: 71% [03], GF: 28%
DECO: 30m for 02:00 [ 38] on Trimix 18/45, SP: 0,0, END: 9m M-Value: 74% [04], GF: 35%
DECO: 27m for 02:00 [ 40] on Trimix 18/45, SP: 0,0, END: 7m M-Value: 76% [04], GF: 41%
DECO: 24m for 03:00 [ 43] on Trimix 18/45, SP: 0,0, END: 6m M-Value: 79% [04], GF: 47%
DECO: 21m for 02:00 [ 45] on Nitrox 50, SP: 0,0, END: 10m M-Value: 81% [05], GF: 53%
DECO: 18m for 03:00 [ 48] on Nitrox 50, SP: 0,0, END: 8m M-Value: 84% [05], GF: 59%
DECO: 15m for 03:00 [ 51] on Nitrox 50, SP: 0,0, END: 6m M-Value: 85% [06], GF: 65%
DECO: 12m for 06:00 [ 57] on Nitrox 50, SP: 0,0, END: 4m M-Value: 88% [06], GF: 72%
DECO: 9m for 08:00 [ 65] on Nitrox 50, SP: 0,0, END: 2m M-Value: 90% [07], GF: 78%
DECO: 6m for 10:00 [ 75] on Oxygène, SP: 0,0, END: 0m M-Value: 92% [08], GF: 84%
DECO: 3m for 18:00 [ 93] on Oxygène, SP: 0,0, END: 0m M-Value: 94% [09], GF: 90%

OTUs : 116 SNC : 64%

Almost equal with OSTC planner, depending on presure and descent speed

I don't understand your results with V-planner and VPM.

With Baltic deco :
ZHL16B : SNC = 60%
VPM nominal : SNC = 53%
VPM +4 : SNC = 64%

[Smiler1968]

heinrichsweikamp Wrote:
-------------------------------------------------------
> Hi,
>
> The deco planer in the OSTC uses the same routine
> then the normal dive mode. You have a few
> simplifications with the planer:
> - infinite descent speed
> - 10m/min ascend speed + 1min between 3m and 0m
> - Simulated dives controlled via a PC software
> (Divinglog, Jdivelog) always use 1000mbar surface
> pressure
>
> Regards,
> Matthias

Thanks for the reply Matthias but I'm afraid I'm still a tad confused. I understand the planner puts you straight to your maximum depth. That would mean a longer bottom time and a higher PPO2 and in turn a higher CNS%. However on mine that is not the case. The ascent speed is set at 10m/min. During my simulation dive I was moving up one metre every 6 seconds (give or take) not exactly scientific I know but should give me very close to the planners ascent rate and therefore should not make any real difference to the total CNS. I didn't run the dive using any other PC based software so the mbar is not an issue.

As I said it was never my intention to compare planners and run times. My concern is whether the 2n planner is calculating the correct CNS for the WHOLE dive.

Regards

Jerry