Surface Interval start...

[cheeseandjamsandwich]

What does this thread tell us about the attitude to reporting of bugs? Should we not bother?
Do the users not want bugs fixed? Because it changes something perhaps, and they hate change...

We're not talking about the colour of the battery or whether the ostc should include functionality that recreational dive computers all have. The definition of Surface Interval is fixed, not negotiable, it's the time the diver has been on the surface, outgassing. And the OSTC happens to be misreporting it for a know reason.

[TnT]

If this was a real bug, then I'm sure HW would fix it in no time. But in this case it's not a bug, and they explained you why. If you are not convinced, that's your problem and you are always free to build a custom firmware.

The OSTC considers your dive finished once the CF02 time has passed. Your surface time starts afterwards. I don't see anything wrong with that. During the CF02 period, the OSTC will stay in dive mode and continue decompression calculations. But because your depth is rougly zero, it's essentially doing the same as during the surface interval: calculating tissue desaturation. Again I see no problem.

If you compare two different dive computers, then there will be inevitable differences between the two. Your Suunto (or any other brand) will likely also calculate different deco schedules. Why do you accept that, but not the difference in surface interval? If you want everything to line up perfectly with another brand, you should stick that brand instead.

Honestly, a difference in surface interval of a few minutes is irrelevant. If you report your surface interval, or use it for manual table based calculations, you always end up with an estimated value, because you don't know in advance the exact time when you'll enter the water. Gearing up, waiting for people before you, etc will all take time that is in the same order of magnitude (and probably larger) as the difference in surface time your are complaining about now.

[scubatinoo]

cheeseandjamsandwich Wrote:
-------------------------------------------------------
> The
> definition of Surface Interval is fixed, not
> negotiable, it's the time the diver has been on
> the surface, outgassing.

Sure? There are actualy several possible points when "surfacing"
can begin:
- the time when you reach the surface
- the time when you spit out the regulator after reaching the surface, and breathing pure air
- the time when you're standing on dry land, breathing air and having no more waterpressure arround any part of your body
- the one before including peeling off your argon filled drysuit, so that you're on dry land, sourrounded by fresh air, and breathing it...
- the last one including sitting in a restaurant and drinking beer

Which one is right if you're talking about offgasing? The first one is zero seconds after the dive, the last one is about half an hour after the dive... So for me using the standard setting with 4 Minutes is OK, because it is somewhere between the first and third point...

[cheeseandjamsandwich]

scubatinoo Wrote:
-------------------------------------------------------
> cheeseandjamsandwich Wrote:
> --------------------------------------------------
> -----
> > The
> > definition of Surface Interval is fixed, not
> > negotiable, it's the time the diver has been on
> > the surface, outgassing.
>
> Sure? There are actualy several possible points
> where "surfacing"
> can begin:
> - the time when you reach the surface
> - the time when you spit out the regulator after
> reaching the surface, and breathing pure air
> - the time when you're standing on dry land,
> breathing air and having no more waterpressure
> arround any part of your body
> - the one before including peeling off your argon
> filled drysuit, so that you're on dry land,
> sourrounded by fresh air, and breathing it...
> - the last one including sitting in a restaurant
> and drinking beer
>
> Which one is right if you're talking about
> offgasing? The first one is zero seconds after the
> dive, the last one is about half an hour after the
> dive... So for me using the standard setting with
> 4 Minutes is OK, because it is somewhere between
> the first and third point...

It's a bit weird arguing about the definition of "surface interval" I thought every diver would easily understand it. The clue is in its name.

When you surface, you are then once again breathing gas/air at ambient pressure... even if you keep your reg in! This is when you're off-gassing, at your final 'depth', i.e. the surface. It's the end of the 'dive' i.e. you're now not underwater at a depth, breathing pressurized gas (i.e. higher than atmospheric pressure).

Unless HW can describe it otherwise, the OSTC does all its calculations correctly, it knows the atmospheric pressure before the dive and knows when your back on the surface, at atmospheric pressure, so it knows you're not on-gassing anymore... so it works out the off-gassing.
I assume, the dive mode time-out is there so that if you pop up to the surface, and then go back down 1-2 minutes later, it doesn't start a fresh new dive, its considered a continuation of the same dive. Correct?
And that the deco calculations work on the pressure, so when at the surface, below it's threshold, it knows it's not on-gassing, it's off gassing... So it's not waiting for the dive mode time-out. Correct?

Why are you so against this being fixed?

[cheeseandjamsandwich]

TnT Wrote:
-------------------------------------------------------
> If this was a real bug, then I'm sure HW would fix
> it in no time. But in this case it's not a bug,
> and they explained you why. If you are not
> convinced, that's your problem and you are always
> free to build a custom firmware.
>
> The OSTC considers your dive finished once the
> CF02 time has passed. Your surface time starts
> afterwards. I don't see anything wrong with that.
> During the CF02 period, the OSTC will stay in dive
> mode and continue decompression calculations. But
> because your depth is rougly zero, it's
> essentially doing the same as during the surface
> interval: calculating tissue desaturation. Again I
> see no problem.
>
> If you compare two different dive computers, then
> there will be inevitable differences between the
> two. Your Suunto (or any other brand) will likely
> also calculate different deco schedules. Why do
> you accept that, but not the difference in surface
> interval? If you want everything to line up
> perfectly with another brand, you should stick
> that brand instead.
>
> Honestly, a difference in surface interval of a
> few minutes is irrelevant. If you report your
> surface interval, or use it for manual table based
> calculations, you always end up with an estimated
> value, because you don't know in advance the exact
> time when you'll enter the water. Gearing up,
> waiting for people before you, etc will all take
> time that is in the same order of magnitude (and
> probably larger) as the difference in surface time
> your are complaining about now.

HW has not explained why this isn't a bug.
Matthias just confirmed how it works at the moment, timing from after the time-out.
If it reports an incorrect value for something, then it needs fixing and could be described as a bug.

But this discussion isn't about the fact that its only a little bit wrong, that won't affect anything, which i have to totally agree... it's about a little feature that is reporting a wrong value for a know reason, it's a no-brainer that it should be corrected, which would probably be an easy code change, and then that'd be the end of it, another bug squashed, more polish on a great produce... But it's being stated that it wont be fixed. With no reasoning. And several users have stated that they really don't want it fixed, with no reasoning.

Why do you not want this fixed? Details please.

[cheeseandjamsandwich]

Just to Clarify it all(?!)

From the U.S Navy Diving Manual rev. 6
[pre]
Surface Interval. In the context of repetitive diving, the surface interval is the
time a diver spends on the surface between dives. It begins as soon as the diver
surfaces and ends as soon as he starts his next descent.
[/pre]


From Wikipedia (100% true always!)
[pre]
The surface interval (SI) or surface interval time (SIT) is the time spent by a
diver at surface pressure after a dive during which inert gas which was still
present at the end of the dive is further eliminated from the tissues.
[/pre]

http://en.wikipedia.org/wiki/Decompress ... e_interval
[pre]http://en.wikipedia.org/wiki/Decompress ... e_interval[/pre]
(Some interesting stuff on this page actually!)

[swissdiving]

Anyone interested in reading the Safety Stop discussioin in 2012?
http://forum.heinrichsweikamp.com/read.php?2,8636,page=1

[sailor]

Hi Rich,

just set CF02 to 30s and you fixed the issue by yourself.
Half a minute should not bother, isn't it?
Dont't let the try and error with 0s bother you.

I believe the reason for this "feature" are the missing wet sensors.
Most other computers have issues with their wet sensors.
I like the OSTC with this missing extra failure point.

You have it in your hand, the OSTC is fully configurable.

Reiner

[cheeseandjamsandwich]

sailor Wrote:
-------------------------------------------------------
> Hi Rich,
>
> just set CF02 to 30s and you fixed the issue by
> yourself.
> Half a minute should not bother, isn't it?
> Dont't let the try and error with 0s bother you.
>
> I believe the reason for this "feature" are the
> missing wet sensors.
> Most other computers have issues with their wet
> sensors.
> I like the OSTC with this missing extra failure
> point.
>
> You have it in your hand, the OSTC is fully
> configurable.
>
> Reiner

I did try this.
But actually, i do need the time-out to be say 4 minutes. It's fairly often i have to re-ascend to sort out diver's under-weighting issues at the start of dives or more often bring up 'air pigs' to put them back on the boat before going back down to the other divers for the last 15 mins, so i need it to stay in dive mode to keep timing the dive as one.
Dive mode time-out is actually set at the correct value i think.
The ostc then behaves like most other dive computers in this respect, and behaves correctly.

But this thread isn't about getting the Surface Interval to read correctly.
As i've expressed above, it's the principle.

* The surface interval is defined clearly, and i didn't expect to have to argue this at all!
* The OSTC is reporting the SI wrong for a clearly understood reason, it's counting the time since the arbitrary dive mode time-out, instead of counting the time at the surface.
* We have users that aren't bothered that it's wrong and therefore think that it should not be fixed, with no explanation. If they're not bothered it's wrong, then they shouldn't be bothered that it gets fixed either.
* And then we have HW which have stated that 'Honestly, we're not going to change this', again with no explanation or reasoning.
* This thread suggests that we perhaps should not report any bugs we discover in case it minutely changes the OSTC is some way that will offend some others users for no reason.

From the HW website:
[pre]
Further development:
Open Source does not mean that everyone using this unit has to write programs, it
means that he can. Users that don't program, but instead notify of errors and give
hints, profit just as much. (Especially considering that there are only few dive
computers on the market that make a firmware update even possible.)
[/pre]


This is just a simple bug that needs fixing!

[Bardass]

this is not a bug, this is a feature !
The CF02 parameter serve to separate two dives in your logbook, it has not impact about the calculation of decompression.

your computer calculates the decompression depending of pressure, regardless of whether you consider that diving is finished or not.
3m under water or on the surface, the computer calculates your decompression. The surface is a deco stop as another.

So the decompression algorithm doesn't need that the SI starts up or not according CF02'value.
So you do not need to worry about SI for your safety.

But rather not to dive 4 times a day :
you are out of any validation experiments of decompression algorithms ...

[cheeseandjamsandwich]

Bardass Wrote:
-------------------------------------------------------
> this is not a bug, this is a feature !
> The CF02 parameter serve to separate two dives in
> your logbook, it has not impact about the
> calculation of decompression.
>
> your computer calculates the decompression
> depending of pressure, regardless of whether you
> consider that diving is finished or not.
> 3m under water or on the surface, the computer
> calculates your decompression. The surface is a
> deco stop as another.
>
> So the decompression algorithm doesn't need that
> the SI starts up or not according CF02'value.
> So you do not need to worry about SI for your
> safety.
>
> But rather not to dive 4 times a day :
> you are out of any validation experiments of
> decompression algorithms ...

Bardass, please re-read my last post.

I agree with what you say above, and you explained the deco calcs better than me.


But it is a bug.

It reports the SI to be a time since CF02 times-out instead of the time on the surface (at surface pressure), so it's giving an incorrect reading.


Why doesn't anyone want to improve this product? To iron out a bug or two?

[scubatinoo]

cheeseandjamsandwich Wrote:
-------------------------------------------------------
> But it is a bug.

Nope, it's not.

As Sailor wrote:
"just set CF02 to 30s and you fixed the issue by yourself".

Just do it!

-D

[cheeseandjamsandwich]

scubatinoo Wrote:
-------------------------------------------------------
> cheeseandjamsandwich Wrote:
> --------------------------------------------------
> -----
> > But it is a bug.
>
> Nope, it's not.
>
> As Sailor wrote:
> "just set CF02 to 30s and you fixed the issue by
> yourself".
>
> Just do it!
>
> -D

????

I can't change CF02 as it's set to a sensible value and it works very well.

Why are you so against this being fixed? Please explain yourself.

[Laurie_the_Knot]

I've read the above correspondence and am amazed at the resistance to correcting an obvious inconsistency in what is otherwise and excellent dive computer algorithm.

I'm still in agreement with 'cheeseandjamsandwich'. The surface interval should reflect the value of CF02 plus the surface time following the timeout of this CF. This information is independent of the outgassing process and more about making surface interval timings more consistent with the definitions as described in the documentation reported and ALL other dive computers and dive timers.

My guess is that it would be a trivial task for the excellent programmers responsible for the algorithm in the OSTC to implement this change. I beg you to seriously consider implementing this change.

As I see it the logic is as follows:
If 'at surface' do count down CF02 from CF02ref. If CF02 = 0 then surface interval = CF02ref.

[adrian-bluescuba]

It is not a bug!
What concerns me more is the inability of an instructor - chease - to calculate his Surface interval.
4 dives a day ia normal on liveaboards etc. so, no need to boast.
Back to the point - this is not a bug. Its a feature for you to adjust it by yourself.
As a couple of people already said. Set it to 30secs and finished. If thats not your way, read the SI Time and add your 4 mins. Should be possible for an Instructor or the buyer of an OSTC ( you remember: this is not ..... )
cheers
adrian

[tiefunten]

I absolutely do not understand why Heinrichsweikamp should change the code and make it more complicated just for those damn and absolutely unimportant four additional minutes SI!?

[jb2cool]

My first post so excuse me if i'm stepping on anyones toes.

One of the benefits of having a delayed switch to surface mode is that if you had a loss of buoyancy on the safety/deco stop or needed to have a look to get your bearings and popped up to the surface for a few seconds before descending again the computer would carry on logging this as one dive. If this went into surface mode immediately the dive would be split into two parts.

Is the default setting of four minutes too much for your circumstances? possibly but you are free to adjust this to a smaller value.

How could you propose this to be 'fixed'? Calculate 'actual surface time' as 'indicated surface time' plus the value of 'CF02'?

[Clownfish]

What is all this argument about?

Rich, do you really use the surface interval on the OSTC to work out when you get back in the water for a second dive and must have it so accurate that you cannot wait till it says 60 minutes? If so, just go in at 56 minutes.

If you are on a liveaboard, then your interval will be set by the boat operation. If on a day boat or shore dive, then it will not matter if you go in at 56 or 60 or 64 minutes. In any case, I would seriously worry about people doing only 60 minute surface intervals anyway.

The computer will work out your off-gassing no matter what. If anything, having it the way it is now is safer, in that the real SI interval is longer than that shown.

Please can this be considered closed, it is getting boring to read all the arguments.

[cheeseandjamsandwich]

Firstly, I think it's polite and normal forum etiquette that if you wish to contribute to a conversation thread, you first read the whole thread, as the discussion will explain the problems, situations, ideas, and determine acknowledged facts along the way.
It seems that some people haven't read the whole thread, or have misunderstood what has been written.
So please read the thread or re-read it before posting.
I.e. RTFT!


Clownfish Wrote:
> Please can this be considered closed, it is
> getting boring to read all the arguments.

No one is forcing anyone to read anything.

[cheeseandjamsandwich]

Let's have a recap, to make it easy to follow.

Facts we know:
1) Surface Interval: This is the time a diver has been on the surface, breathing air/gas at surface pressure, after a dive.
2) OSTC's Surface Interval: This is the time since the Dive Mode timed-out (CF02), which by default is 240 seconds, or 4 minutes, after the diver had surfaced.
3) A Surface Interval time reported by different dive computers worn by the same diver should be expected to be pretty much identical.
4) The OSTC's deco calculations are not affected in any way by CF02 or the reported surface interval, it purely monitors the pressure.
5) A few minutes (say 4) difference in the surface interval isn't going to make a significant difference to off-gassing, gaining credit for the no-deco/deco times on the next dive.
6) "A software bug is an error, flaw, failure, or fault in a computer program or system that causes it to produce an incorrect or unexpected result, or to behave in unintended ways." (wikipedia)
7) The OSTC reports the surface interval to be 4 minutes shorter than the time the diver has been on the surface, this is unexpected, and an incorrect result, so it can be described as a software (firmware) bug.
8) The Dive Mode Time-Out, CF02 is set at 4 minutes by default, and this is a sensible time for many divers.
9) Not having an adequate dive mode time-out might cause a new dive to start if a diver has had to briefly surface before re-descending. This can mean the diver cannot then track the total dive time that say his buddies/customers have.
10) A product where the designers/creators have paid much attention to detail is greatly appreciated by its users.
11) This appears to be a small bug and probably easy to correct in coding the firmware.


Observations we can make:
a) Not all divers need to know the surface interval. Some dive once a day, or many hours apart.
b) Some divers do need to know what the surface interval is for various reasons like the dive centre boss insists that there's a minimum of one hour between dives, the boat captain wants to get back for lunch asap, the boat is going out again in the afternoon so it needs to get back for a prompt turn around.
c) Not many/any of these reasons are critical to off-gassing/deco considerations, but more critical to the general running and logistics of a dive operation.
d) It is perfectly possible for the diver to 'calculate' the real surface interval from the OSTC's reported surface interval, but this seems like an unnecessary task.
d) Doing multiple dives on sites with sloping reefs means that the profiles that are done often mean long surface intervals are not as important as say wreck dives with squarer profiles.
e) All the details about why someone perhaps needs to know the surface interval or how much a surface interval will affect the deco of the next dive are not needed to be known or discussed when talking about this error in the OSTC's surface interval.
f) This bug is considered to be logical, i.e. it's reporting an incorrect time, rather than an subjective. e.g. i don't like the battery colour purple, or, i don't want a certain feature because i don't need it.
g) Calling this a feature or a bug is irrelevant to this conversation as the OP's initial and continuing intention for this thread is to just get the OSTC's surface interval to report the correct time.

And Also:
h) No one is forcing anyone to read anything. If you find something boring to read, don't read it.
i) It sometimes seems like some members fail to read/understand the entire thread so that they repeat stuff that has been discussed/answered before.
j) When reporting a bug, it is surprising when users object to fixing it.
k) Forum members objecting to changing something that they don't find important or care about tends to cause threads to go on a bit...


Thanks once again to Laurie for your support.

[scubatinoo]

Rich, the surface time starts when your dive computer tells you! Believe it or not.

If you refer to something else (navy tables), it must not be necessarily valid for your dive computer (based on Bühlmann ZH-L). Every dive computer has it's own rules, accept it.

I'm off now. EOD

[swissdiving]

tinoo
(tu)

[Stephane]

Rich,

As the code is open source, you are free to correct what you think is a bug. HW published all the informations needed to achieve such a task.
If for any reason you are not able to do the change by yourself, you will have to live with it.

[cheeseandjamsandwich]

Stephane Wrote:
-------------------------------------------------------
> Rich,
>
> As the code is open source, you are free to
> correct what you think is a bug. HW published all
> the informations needed to achieve such a task.
> If for any reason you are not able to do the
> change by yourself, you will have to live with it.

As i posted earlier, but forgot to put in the summary, silly me.
[pre]
Further development:
Open Source does not mean that everyone using this unit has to write programs, it
means that he can. Users that don't program, but instead notify of errors and give
hints, profit just as much. (Especially considering that there are only few dive
computers on the market that make a firmware update even possible.)
[/pre]
(From the HW website)

My programming skills are limited to a bit of Pascal & VB, it's not something i'd want to trust in a key part of diving safety.

HW, etc. that code the firmware have done an excellent job so far and have gained a great reputation. I trust them.

I'm just 'notifying them of an error' I've found.

[cheeseandjamsandwich]

To scubatinoo, Bumlerd, Bardass, TnT, adrian-bluescuba, tiefunten, Clownfish & Stephane,

You guys appear to be objecting to the plea for the OSTC's 'Surface Interval' feature to be modified so that it reports the time a diver has been on the surface breathing air at surface pressure, instead of this service time minus 240 seconds.

1) Why do you think that this shouldn't be modified?
2) How will it affect you, when diving with your OSTC, if it was modified?
3) Why do you think that the OSTC shouldn't report an SI that follows what the diving textbooks, manuals, etc define it as?
4) Why do you think that other users don't need to know what their true surface interval is.

Please clearly explain the above & justify your positions.
I've spent time to clearly describe the issue and justify why i think it should be fixed.

You cannot just jump into a thread and object to something unless you can justify what you say. That's trolling.

Explain yourselves.