On 13/03/2018 14:49, Robert Helling wrote:

Am 13.03.2018 um 12:25 schrieb Anton Lundin <gla...@acc.umu.se>:

 From subsurface point of view, it really doesn't matter if we represent
a bailout as a gasswitch event or not. The problem with the gasswitch
and setpoint change, is that it doesn't work for dives with po2 sensors
or the SCR steady state approximation.

Sorry, I don‘t get it. What is the problem with pO2 Sensors?

A setpoint change to 0 is sort of a clever hack which just works for
planed/setpoint-only CCR dives, and not for CCR dives with po2-sensors,
or SCR dives.

I'd suggest we clean that up into some bailout sematics which works for
both SCR and CCR code, with or without o2 sensors.

If we implement that as a divemode switching event, a gaschange event
with some special flags, i don't really have a opinion until i see a
real suggestion. Nothing says we can't have a gaschange event which
switches to the same gas as we're currently using...
You could always interpret „gas switch“ not as „switch of gas in cylinder“ but 
as „switch of breathing gas“ as that what PSCR divers experience when going 
from the loop to OC.
I would say, the main difference is to make „PSCR mode“ not a global thing for 
a dive but more local in time. Note that this is already the case for „CCR 
mode“: We have set point that can change over time with 0 indicating OC and 
„CCR mode“ in a more strict sense (as in the combo box) is simply a dive that 
has at least at some part non-zero set-point (but we don’t use that to 
determine the breathing gas at any moment).

Does that make sense?


This would affect the whole current dive equipment model with the cylinder structures and their definitions. Think of the CCR case where the 1st cylinder is O2 and the remaining one diluent. How would you make this a local mode in time within a dive? And gas composition varies all the time in order to keep pO2 constant? Which gas would one choose? There would be continuous gas switches. As for SCR, remember the way it is used at present, it is just a special case of CCR.

But, it's worth entertaining your proposal. Let's see where this discussion goes...

Kind regards,

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