Odd Profile Change

[Craig Ballingall]

Hi, I have a new OSTC 2N, which I'm very please with but found an odd feature... While ascending from a 45meter trimix dive, I completed a 5 minute stop at 21m (I've added 5 mins as the minumum stop time for gas switches) and then ascended as normal through the stops to 6 meters. When I reached 6 meters I performed a switch to O2 and when I looked to the hand set it was asking me to return to 21m! I told it I had switched to o2 and it immediatly recalculated and was happy (although at 6m it either complains you're too shallow or your pp02 is too high). I downloaded the log and the sudden drop in deco ceiling is also shown in the log.. is this a bug with the gas switch planning or something else?

[heinrichsweikamp]

Hi,

See here: http://www.heinrichsweikamp.com/read.php?2,6129

"- A CF55 setting>0 in combination with more then three gases caused additional deco stops at 21m"

Regards,
Matthias

[Craig Ballingall]

Excellent, I'll upgrade... I'll have to go diving again just to be sure it works

[heinrichsweikamp]

Hi,

I think this varies but 5mins is a lot of time for a gas change, isn't it?

regards,
Matthias

[Craig Ballingall]

It is, it takes me no time at all to do the switch.... I've just found that I ever feel tired after a dive if I pad the 21 meter stop when switching off the helium and it just means it gets calculated into my ascent time. I stay at 6 meters for the last stops usually (unless it's been very deep and CNS is an issue) so the padding isn't a factor

[JeanDo]

If you just two switches (21m and 6m) it is exactly what CF55 was made for.
If you have more switches, beware it will add stops of at least 5mn for each one...

Bit what you describe also look like you need more deep stops... What is your settings and profile ? Did you ever consider use a lower GF_low value ?

Regards,