Help with CCR mode

[david tobin]

I am about to embark on the rebreather route, training booked over Easter and unit,Inspiration Vision, ordered.

I have playing with simulator in CCR mode but wondered if there is any guidance/advice out there on using the OSTC as a backup to the Vision electronics.

[boefst]

Hi,

IMHO, just set it and forget it.

Use the same GF and same diluent as in your Vision. Enter your BO-gas as gas no.1, so you can reach it easily with "Left, Right, Right, Right, Right in a BO situation.

Set 1.30 as PO2 and your OSTC will most often be just a little more conservative than your Vision. That way, you can use the easy-to-read OSTC as your primary display for checking time, depth and deco-stops and the Vision only for confirmation of PO2 and stops, and for communication with the electronics .

During training it is perhaps better to use the OSTC as backup, as you say, but my advice on the settings would be the same.

[cparsons]

I would agree with everything said by 'boefst' - that's the way I use mine, set to 1.30 all the time

The training will emphasis the contant looking at the handset (I have a Vision too) which is absolutely correct but the OSTC has a fabulous display underwater, (puts the Vision to shame...) so I tend to be watching that for the deco most of the time

Tweak the gradient factors etc to match the Vision if you use these

Best of luck, I have had my Vision for several years, best decision I ever made

Cheers

[Edward]

I crossed over to CCR not too long ago and using a JJ.

I had my OSTC for a few years now. Its easy to use when diving OC but I am totally clueless as to how it should be set as a backup computer when I am diving CC.

So far I figured that I just have to set the first of the setpoint SP#1 to 1.3 considering that the OSTC does not have the auto switch feature and leave the other 2 setpoint on default.

Do you still set CF39 to 1 / on as well?

When you do a bail out, besides selecting the correct bailout gas, I assumed you will need to change the deco type to OC as well? Is this correct?

Are there any comprehensive notes and steps to use OSTC as the backup for CCR?

Thanks in advance.

[heinrichsweikamp]

Hi,

CF39=ON adjusts the setpoint to physical possible levels. Example: A Setpoint of 1,6bar in 3m depth is just not possible with a CCR, so the OSTC will adjust the setpoint to 1,3bar then.

When switching to bailout, the OSTC will be in OC mode temporally.

Note that Diluents and Bailouts have been separated recently. Depending on the firmware you use you have to make sure to setup both (Diluents and OC Gases/Bailout gases).

regards,
Matthias

[David Boileau]

Hi,

CF39 is most useful for mCCR guys (but not only for them)

I dive with a rEvo III mCCR. I have to maintain ppO2 manually, so it's possible that the real ppO2 is sligthly under the targeted ppO2. So I take a safety margin for deco calculation.

My target ppO2 is 1.3
As a safety margin, the OSTC setpoint is 1.15 (rEvodream HUD starts blinking with ppo2 (OSTC setpoint) and it's nice to have CF39 on.

Example : diluent air, depth 47m (I know... air diluent should be 40m max...), 0,21 x 5,7 = 1,2 - OSTC will use 1,2 instead of 1,15 for deco calculation.

It's also a nice feature if you start on a 0,7 setpoint in the OSTC and forget to switch to 1,15... Hum hum...



Note : I have also a connected shearwater (reads the cells, but no controller) - the shearwater of course knows the real ppO2 and calculates the deco with it. Practically the difference is small.

[dmainou]

Matthias,

Do you think we'll have a new stable soon?

No pressure.

D