hwOS Tech: 2.97 released

[heinrichsweikamp]

Hello,

The new hwOS Tech (for OSTC3, plus, cR and OSTC 2) firmware 2.97 is now available for download:
https://heinrichsweikamp.com/service/firmwares

The firmware itself can be set to English, Deutsch, Italiano and Français. The firmware is split into two language versions: English + German and French + Italian. Make sure to install the correct HEX file.

Due to several internal improvements this update needs to reset your settings to default. Your logbook will remain, of course!

Die neue hwOS Tech Firmware 2.97 (Für alle OSTC3, plus (Tech-Versionen), cR and OSTC 2 (Bei Mod. 2017 Tech-Versionen)) ist jetzt zum kostenlosen Download verfügbar:
https://heinrichsweikamp.com/service/firmwares

Die Firmware selbst kann auf Englisch, Deutsch, Italienisch und Französisch gestellt werden. Die Firmware ist auf zwei Versionen gesplittet (Englisch + Deutsch sowie Französisch und Italienisch), achtet darauf die richtige HEX Datei zu installieren.

Aufgrund zahlreicher interner Verbesserungen setzt dieses Update leider alle Einstellungen auf den Defaultwert. Das Logbuch bleibt selbstverständlich erhalten!

Changes/Änderungen:
[2.97]
NEW: On-the-fly Gas needs calculations for all active gases
NEW: Internal deco calculator shows deco plan and gas beeds for Bailout case
NEW: CNS now, CNS in xx minutes, CNS if bailout plan is used and CNS when surfaced (Including all deco stops) is shown
NEW: Bailout TTS is computed in CCR mode (optionally) with gas needs for all bailout gases and all deco stops
NEW: Warning if an isobaric counter diffusion occurs (also in internal planner)
NEW: Warning "X-ZHL16-X" if deco model is used beyond theoretical limits
NEW: Show "Deco Zone" if we are in deco and at least one tissue is off-gassing
CHANGE: Internal deco routines heavily optimised for speed and code size
CHANGE: Limit button sensitivity to 80%
BUGFIX: Auto-Gain for newer compass versions did not work (Which decreased accuracy of heading)
CHANGE: Make disabled gases darker in surface mode (Common issue for color-blind divers)
CHANGE: French and Italien language updates
NEW: Independent saturation/desaturation multipliers for GF and non-GF Deco modes
CHANGE: Non-updated values are shown in dark blue (e.g. after a gas change) until values are valid again
CHANGE: USB OSTC (OSTC 3 and OSTC cR) will enter USB mode from Menu only

Details on hwOS: https://heinrichsweikamp.com/hw-os

How to install: read.php?6,14509

Regards,
Matthias

[dadefay]

Great ! But it would have deserved to be 3.0 !

Thanks for your work.

[Ralph]

Hi Didier,

thanks for the honor granted, but we'll keep the magic 3.0 for a version
with an even improved advice/attention/warning system, better-gas function,
a new CCR cave bailout prediction/warning and support for the new pressure
transmitters on the OSTC 2 TR family member...

Have fun,
Ralph

[algo]

Hi,

yesterday i did the first dive with the 2.97 version...

I really like the blind mode. It is like magic under water, just seeing what you really need and that in big numbers!

But one thing surprised me a little bit. I did a dive which resulted in a deco of 1min/12m, 2min/9m and 8min/6m. This at the end gave me a "No Fly" of just 40 Minutes! The new "No Fly" option is set to "Fliegen". My buddies (OSTC4 and Suunto Viper) had >12h!

Alex

[Ralph]

Hi Alex,

flying-after-diving waiting time is a kind of "poor cousin" in diving. Most dive computer implementations stick to the guidelines put out by DAN etc. - the well known 12 / 18 / 24 hours intervals (well, the OSTC4 too). Hence, there are count-down timers in the code that simply get triggered at the end of a first or repetitive dive and clock-down the given hours. Frankly speaking, it's like using a classic look-up diving table for the no-fly-time while the dive itself is computed according to Bühlmanns laws or whatever model the computer uses. The thing is, these 12 / 18 / 24 hours rules or recommondations are set up as a general-applicable, safe-side rule and do not reflect your personal actual dive profiles, and even more important the gases you breathed (i assume they are made on pure air diving). But especially if you deco on O2-rich gases, your body tissues clean-up much faster than assumed by these rules.
In the recent OSTC 2 hwos firmware, the no-fly-time is computed in the same way like an ascent from a given depth to surface, just that the depth now is your after-surfacing tissue loads and the surface you are heading for is the reduced ambient pressure in the aircraft's cabin. The resulting deco stop time is then shown as the no-fly-time. Actually it reacts to changing ambient pressure as if you were diving: going a little bit uphill (aka reducing the ambient pressure) will fasten offgassing and shorten no-fly-time, "good weather" = high air pressure will increase no-fly-time.
Why does the hwos code development choose to do it this way? Well, because Mr. Bühlmann wrote in his books that his model is also valid for reduced surface pressures and all the mountain diving tables he produced made benefit & proofed this validity. So if you trust in the Bühlmann model while diving underwater, there is little point in not trusting it when calculating the necessary decompression before ascending in an aircraft's pressure cabin to cabin altitude. Sure - restrictions and limits of the model remain the same: if your body is heavily loaded with microbubbles, if you are dehydrated etc. pp., the model and the figures it produces won't be vaild for you, regardless whether you are diving or sitting in the airport terminal...

best regards,
Ralph

[Clownfish]

Dived today.

On the alternate screen (but not sure about main screen), the safety stop countdown went like 14 13, 12 11, 10 9, etc. The gaps between the two numbers was not one second, but between the pairs, it was longer than one second. Only noticed this right near the end of the stop, so did not have time to check if it was like this on the main screen.

Also, there is no ascent graph now on alternate screen.

[DennisA]

Is the nofly time calculated on the basis on the pressurised cabin or the actual pressure outside at typical cruising altitude?

Imagine a experiencing a pressure drop in the cabin and then having to deal with DCS on top the emergency landing etc...

[Ralph]

Hi Michael,

thanks for the info! Were the deviations from regular seconds massive or just slight? If safety stop countdown was shown i assume you were inside NDL (i.e. no deco).

The ascent graph isn't in the alternate screen on purpose, it would graphically collide with other elements...

Cheers,
Ralph

[algo]

@Ralph: thank you for the explanation!

[Ralph]

Hi Dennis,

in setting "flying", a target pressure of 0,6 bar is used. This is the value used by Bühlmann in his books. Actually, current commercial passenger aircrafts with pressurised cabins have a cabin pressure that is a bit higher than 0,6 bar, which works to the safe side.
In aircraft emergency procedures, cabin pressure is assumed to go through a state of so-called "excessive cabin altitude" (too low cabin pressure), which triggers warnings in the cockpit as well as some auto-functions. For example the oxygen masks come out automatically at preset cabin altitudes if not released by the flight crew manually before. If you find them dangling in front of you, take them and breath from them and do not forget to give the hose/lanyard a sharp pull beforehand because elsewise the oxy generator won't be ignited and start producing oxygen and/or the supply valve not opened. This all happens way before the cabin pressure equalised with outside pressure. If it would in an all-of-a-sudden due to a big bang, well, flying is one of the safest things, but in such a situation all passengers (even the none-divers!) would suffer DCS and whether the aircraft would make it to a landing would be another question, too. But given a "leaking" cabin, after oxy masks out the pilots would immediatly initiate a sharp emergency descent to about 2.400 - 3.000 meters altitude, which should be low enough even for the divers on board. You can regard it as an a few minutes lasting ommitted decompression.
By the way, needing to be able to make an emegency desenct is the reason why most passenger routes circumnavigate the Himalaya area - it's simply not possible to go down enough there. Few aircrafts can fly there, they have extended storage of bottled oxygen on board to be able to stay higher for longer times while supplying all passengers for these extended times. Maybe as a diver returning from a dive trip, you should avoid these flight routes...
One last tip: the typically used chemical oxy generators just run for a couple of minutes. If you had to use them and/or you suspect an emerging DCS problem with you, you can ask the crew for therapeutic oxygen. It's the green cylinders with demand regulators that you probably have seen before stored in the overhead compartments and other places throuhout the cabin. Although they are primarily supposed for the cabin crew, when providing good reason they'll be given to you, too.

safe flying,
Ralph



PS: for the altitude settings 1000 / 2000 / 3000 m the pressures have been selected by using the barometric altitude equation in combination with "bad weather" i.e. an additional low pressure fraction

[Rob]

Hi Ralph,

thank you for the explanations. (And please let the do not fly time as it is and never ever change it to the 12 24 36hours that other Computers show )

I have an idea to improve this. What i am missing, when im diving in Austria for example is.
What is the maximum height i can go with the tissue load i have.
So, is it possible, to show the maximum height (according to the atmpspheric pressure) i can go.
i.E.

do not fly 3:30
max Height 1300m

Then i know that a mountain pass at 1200m wont be a problem.

Regards
Rob

[Ralph]

Hi Rob,

this feature request was sure to come up...

I'll put it on my ideas list but please do not tell Matthias about it as i'm already pumping features into the hwos code at a rate he hardly can keep pace with...
Anyhow, right from now you can set no-fly to altitutes of 1000 / 2000 / 3000 meters via the settings menu and the OSTC will give you respective no-alt-times (no no-alt-time shown -> you are cleared for that hight).

By the way: the new firmware comes with a new revision of the options table, so you may update your tool... Pls. do not hesitate to contact me if you have any questions on the added options.

BR
Ralph

[Rob]

Hi Ralph,

i'm working on it, besides other things.
Are you doing the paperwork for the new functions too?
(the hwos_interface.odt)

Maybe its a good idea to exchange email adresses.
Send me a short mail to ostctools@angermayr.eu.

Regards
Rob

[heinrichsweikamp]

The hwos_interface.odt is maintained by currently.

regards,
Matthias

[Rob]

Hi Mattias,

i think i would be a good idea to have the firmware version in a column next to the read/write settings.

i.e. 0x5C ...... 2.97

Than i can check if the funcion is already availible with the firmware on the connected ostc.


Regards
Rob

[ClaudeDive]

Hi Matthias,

Thank you Matthias for v2.97 and these developments and improvements,

Some remarks and questions about this very rich version,

OC Gas Setup > OC Gas List:
It would be nice to be able to program a depth of change on the descent for gas "Travel" with this depth the OSTC offers a change, with validation by a simple press of the right button, for the "First Gas" or in other words the "Botton Gas"
In the same way that we program the depths a change for "Deco Gas" to the ascent

Simulator or Dive:
- Does the "Set Marker" function in French "Repère" correspond to a marking on the newspaper of a characteristic point of the dive?

Simulator > Deco Calculations:
- For "Gas Use" what is the "Bar" marking for since there is no Pressure info but a "Gas Need" info in Liter?

Simulator > Deco Calculations and Simulator:
I took over the previous simulation with your example and the same parameters:
The parameters are not optimized, but it's a realistic example,
Programming of gases on OSTC 3 v2.97 latest version of 01.03.2018:
Depth 120 m - Time 11 min - GF 10/85
Consumption: Descent and bottom: 15L / mn - Deco: 15 L / mn - Fixed ascent speed: 10 m / mn
- G1: Travel: 50/15 > Volume 7 L - Pressure 200 bar > Without Depth of Change > see request above,
- G2: First: 10/70 > Volume 24 L - Pressure 200 bar > "Bottom Gas"
- G3: Deco1: 25/45 > Volume 7 L - Pressure 200 bar > Depth of Change 54 m
- G4: Deco2: 50/15 > Volume 7 L - Pressure 200 bar > Depth of Change 21 m
- G5: Deco3: Nx80 > Volume 11 L - Pressure 200 bar > Depth of Change 9 m

Simulator > Deco Calculations :
OSTC Gas Need: and results V-Planner in comparison with conservatism +3
- G1: 50/15: 0
- G2: 10/70: 3897 L > V-Planner: 3658 L
- G3: 25/45: 1830 L > V-Planner: 1584 L
- G4: 50/15: 1149 L > V-Planner: 924 L
- G5: Nx80: 1613 L > V-Planner: 1173 L
> DTR: 141 mn > DTR: 124 mn
the results are consistent, although with differences, but these are justified by decompression calculations different and deco stop times different,
We will keep in mind that for G3: 25/45 we have with OSTC 23 mn of recovery and levels and with V-Planner 24 mn therefore virtually identical values,
[img]file.php?6,file=997,filename=20180302_021107a.jpg[/img]

Simulator > Start Simulator:
I start the simulator with 120 m:
For the same dive with the same computer and the same parameters, we have quite different results for:
The DTR and gas requirements between modes: Deco Calculations and Simulation:
With a DTR that goes from 141 mn in Deco Calculations to 125 mn and 131 mn in Simulation
- G2: 10/70 between Deco Calculations: 3897 L and the Simulation: Gas Need 133 bar (133 b x 24 L = 3192 L)
> Delta Gas Need in Simulation: - 705 L
- G3: 25/45 between Deco Calculations: 1830 L and the Simulation: Gas Need 360 bar (360 b x 7 L = 2520 L)
> Delta Gas Need in Simulation: + 690 L
- G4: 50/15 between Deco Calculations: 1149 L and the Simulation: Gas Need 218 bar (218 b x 7 L = 1526 L)
> Delta Gas Need in Simulation: + 377 L
- G5: Nx80 between Deco Calculations: 1613 L and the Simulation: Gas Need 196 bar (196 b x 11 L = 2156 L)
> Delta Gas Need in Simulation: + 543 L
[img]file.php?6,file=998,filename=20180303_110111a.jpg[/img]
[img]file.php?6,file=999,filename=20180303_105336a.jpg[/img]

Questions: With the same computer and the same settings,
- How can one explain such variations of Gas Need in Simulation? While the Gas
Need with the Dive Plan is coherent, this can only create a great stress in diving (G3: 25/45> 360 bars!) If the parameters during the actual dive are identical to those of Simulation, which should normally be the case,
- Why such variations from DTR (up to 16 min) between Deco Calculations and Simulation?
- Why differences (6 min) on several successive Deco Calculations with strictly identical parameters?

Regards,

[Ralph]

Hi Claude,

thanks for your feedback and questions! We'll have a detailed look in the simulation results you provided and come back on you soon.

Some first answers to:

OC Gas Setup > OC Gas List: It would be nice to be able to program a depth of change on the descent for gas "Travel" with this depth the OSTC offers a change, with validation by a simple press of the right button, for the "First Gas" or in other words the "Botton Gas". In the same way that we program the depths a change for "Deco Gas" to the ascent.

The notions of 'first gas' versus a 'bottom gas' have been discussed just recently. As a matter of fact, the programming logic inside the OSTC heavily makes use of the fact that a dedicated 'first' gas must exist and that it has no depth (aka 0m) assigned. So any changes here would require a lot of code to be rewritten.
Gas changes on the way down, triggered by change depths, are also not part of OSTC logics at times. On the way up the cues to change gas are shown when one has passed over the change depth, whereas on the way down the cues would need to come before crossing that depth. That would require a whole bunch of new code. On the other had, the OSTCs do give a warning when the current gas has a too high ppO2 (configured through deco settings, max ppO2), so that can also be used as the cue to switch from the first to the travel/bottom gas. I am currently working on further improvements of the color-coding of the gases and the better-gas-function. When finished it will provide you a quite comfortable way to switch to the most appropriate gas for the current depth, including switches on decent.


Simulator > Deco Calculations: - For "Gas Use" what is the "Bar" marking for since there is no Pressure info but a "Gas Need" info in Liter?

In the last firmware version the gas use numbers were given without any unit. Then the gas needs calculations during divemode were introduced, delivering numbers in Bar. To eliminate potential source of confusion, the simulator results which are in volume should receive a display of unit, too. So the choices were "Liters" or "Bar Liters". Technically correct is "Bar Liters" as the results are a product of volume and pressure. Maybe more practical would indeed be just "Liters". This was a very late addition to the code, so maybe we'll go to just "Liters" with the next firmware version - to be decided yet...

BR
Ralph

[Clownfish]

Ralph Wrote:
-------------------------------------------------------
> Hi Michael,
>
> thanks for the info! Were the deviations from
> regular seconds massive or just slight? If safety
> stop countdown was shown i assume you were inside
> NDL (i.e. no deco).
>
> The ascent graph isn't in the alternate screen on
> purpose, it would graphically collide with other
> elements...
>
> Cheers,
> Ralph
Yes, a no deco dive. The difference was very noticeable. I had thought that the gaps between "seconds" was say 1.5, 0.5, 1.5, 0.5 etc. I had another HW computer running at the same time also doing a safety stop countdown, but this one had finished before the one running HW2.97. Since they should finish within a few seconds of each other, I am now wondering if the countdown is not accurate and the time between two seconds was actually more than two seconds. Not sure of this though and will not be diving till next Sunday due to weather.

[Ralph]

I checked the Safety Stop Countdown in simulation mode and found it to run accurate - so it needs more testing in this point. Maybe you can provide a procedure that reproduces the problem? What i did see "hopping" was the dive-timeout countdown that is shown after the dive in the upper right corner before the computer goes to surface mode.
Anyhow, these are "just" optical problems. The timebases are updated in an interrupt routine that gets called on the second by the hardware. The rest of the software runs in a one-second round-robin loop, doing the vaste of the outputs first and then the calculations. But some outputs are done after the calculations and as the runtime of the calculations always varies a bit there is a jitter in the timing of these after-calculations outputs. Normally this jitter is not visible - exept when outputing counting seconds...

BR
Ralph

[heinrichsweikamp]

Hi,

Ralph Wrote:
-------------------------------------------------------
> I checked the Safety Stop Countdown in simulation
> mode and found it to run accurate - so it needs

It's the display in the alternate Layout aka "Blindmode". The safety stop countdown is a bit jumpy but the overall time period of the countdown is definitely correct.

Regards,
Matthias

[ClaudeDive]

Hi Ralph,

Thank you for your clear answers,

- I Understand your answer for the "Travel Gas"

- Calculations Deco (Dive Plan): If we have the info in Liters it would be clearer with only the marking "Liters"
We could also have the info in Bar on Deco Calculations (Diving Plan)
But the info in Liter seems to me preferable to an info in Bar for the Dive Plan, and allows to ask the question of the volume of the tank,
For its part the info in Bar would also alert on the choice of volume of the tank ... so to see ?

- Similateur: the info in Bar is perfect, and easier to manage while diving,

- I didn't have an answer on the "Set Marker" function in French "Repère"

Regards

[Ralph]

Fully with you - bar is the prefered measure under water as it is what is shown on the SPGs and Liters is for the planning phase when one hasn't decided on the cylinder sizes yet.

The "Set Marker" function places an artificial alarm into the dive recording which can be shown along the other "real" alarms when downloading the dive into 3rd party logbook software. Not sure if the markers are also shown in the OSTC onboard logbook. -> Matthias to answer.
You can use the marker to e.g. indicate when a dive was turned. I sometimes use them on wreaks that lay on a slope to memorise the depth of the bow and stern or alike.

-R.

[heinrichsweikamp]

There's a small "m" in the internal logbook pinned to the profile.

regards,
Matthias

[Ralph]

Hello ClaudeDive,

havn't had a chance so far to do an in-depth investigation of the anomaly in the gas needs calculation you reported, but i just spotted that you have configured the same gas (50/15 in your case) twice. There is a weakness in the deco code when having to deal with two equivialent gases to choose from, maybe there's a connection to your case.

BR
Ralph

[ClaudeDive]

Hi Ralph

Normally No, this is the classic hypoxic diving procedure (10/70),
To use a Deco gas (50/15) for the start of the descent in "Travel gas", of course it's the same gas, but in the Dive Plan one is G1 and the other is G4

- G1: 50/15 is the "Travel Gas"
- G4: 50/15 is the second "Deco Gas"

There is perhaps an interest in differentiating them in addition to G1 and G4, by the depth of change of gas at the descent for one and the ascent for the other, but as you say it requires rewrite a lot of code, so to see ...

According to the personal choice of the diver the "Travel Gas" can be:
Used and programmed on the OSTC, this is the normal procedure
Used and ignored on the OSTC, which changes the Deco Calculation very little

Regards