forum.heinrichsweikamp.com

Hi,

I got something rather 'unexpected' going on with the desaturation time: it's dropping faster than 'real time'. If I do my last dive in the evening, ending with a desat time of about 25-30 hours, the next day, when I wake up, desat time is decreased to 0 - and I don't sleep 25 hours/night.

Today, I had a desat time of >34hours, so I decided to check the change of desat time during about 20 minutes. This is each time 'real time - desat time':
11h48 - 34h29; 11h49 - 34h27; 11h50 - 34h25; 11h51 - 34h23; 11h52 - 34h22, 11h53 - 34h20; 11h54 - 34h18; 11h55 - 34h16; 11h56 - 34h14; 11h57 - 34h12; 11h58 - 34h10; 11h59 - 34h10; 12h00 - 34h08; 12h01 - 34h07; 12h02 - 34h05; 12h03 - 34h03; 12h04 - 34h01; 12h05; 33h59; 12h06 - 33h57; 12h11 - 33h48

I changed the default gas at 12h00 from nitrox 32 to air, which didn't make any difference (as expected, I just wanted to make sure that this was not the problem). As you can see, the desat time drops more or less twice as fast as expected/real time.

I'm using firmware version 1.40, GF 15/80 and saturation and desaturation factor were set to the default values of 110% and 90% respectively. The last three dives (today), the values were set to 115% and 75%.

What can be the cause of this strange, or to me unexpected, behaviour? (Or is there anything else I can test?)

Thanks, Kurt

Hello Kurt,

I've now simulated 4 different dives with four OSTCs (ZH-L16 GF and ZH-L16 OC) here on my table and will report the difference between real and calculated time tomorrow. All tests were made with the default CF.

One thing is that the desat.-time is calculated based on the current ambient pressure every minute (For constant compensation of low ambient pressure diving).

Regards,
Matthias

Hello Kurt,

We can confirm that there is an issue with the Desat.-time. When putting the desaturation multiplier to 70% it's fine.
We definitely take care of that in the next release. Some users also mentioned that the displayed Desat.-time is too long compared with other computers, so this is more likely an issue of the routine that calculates the amount of desaturation time then a bug in the decay of it.

regards,
Matthias