OSTC2 CNS

OSTC's running hwOS sport or tech
Post Reply
kestas
Posts: 3
Joined: 22 Mar 2016, 15:51

OSTC2 CNS

Post by kestas »

Hello,

Is it possible to see CNS level in dive mode on OSTC2 display? I see it in the logs after the dive, but I was unable to get it displayed during the dive (firmware v2.07).

Best regards,
Kestas
sailor
Posts: 401
Joined: 11 Apr 2008, 23:16

Re: OSTC2 CNS

Post by sailor »

It will automatically show once the limit is reached, don't ask me for the limit. For the older MK2 models it was possible to change the limit for the display of CNS.
kestas
Posts: 3
Joined: 22 Mar 2016, 15:51

Re: OSTC2 CNS

Post by kestas »

From the source code I would suspect something should be visible once CNS has reached 70% (hwos_code/src/hwos.inc):
[pre]
124 #DEFINE cns_display_high .70 ; [%]
125 #DEFINE cns_warning_high .100 ; [%]
[/pre]
These defines are used in check_cns_violation routine (hwos_code/srcdivemode.asm:1761-1785). I'm not familiar with PIC assembly programming, so I am not sure if my guess is correct.

I tried runing dive simulation on OSTC2: 6m, 61 minutes, 100% O2. Haven't noticed any CNS display. To my best knowledge, with these parameters 70% CNS should be reached after ~30 minutes and 100% after ~45 minutes (NOAA tables, Subsurface simulator).

Some details about CNS calculation and display would be helpful.

Best regards,
Kestas
heinrichsweikamp
Posts: 4465
Joined: 13 May 2007, 18:07

Re: OSTC2 CNS

Post by heinrichsweikamp »

Hello,

It's shown (As you found out in the code) from 70% and more. More then 100% will display it in red. CNS is calculated as described in this paper:
Arieli et all.(2002): Modeling pulmonary and CNS O2 toxicity: J Appl Physiol 92: 248--256, 2002, doi:10.1152/japplphysiol.00434.2001

http://www.tecvault.t101.ro/Modeling%20 ... humans.doc

Regards,
Matthias
Post Reply