History behind Dive computer error mode

[flots am]

When the computer says ERR, it still gives time and depth.

Uwatec SmartComs were famous for saying things like "E7" and freezing, or just dying.

There's no guarantee you'll get time or depth or that either one will be accurate.

 

[boulderjohn]

Uwatec SmartComs were famous for saying things like "E7" and freezing, or just dying.

There's no guarantee you'll get time or depth or that either one will be accurate.

...and that is a good reason to have a backup.

My point was that the argument that paper produced dive plans don't fail is incorrect, because they require time pieces and depth gauges that are equally prone to failure and equally in need of a backup.

 

[commitch]

It seems to me that all approaches have strengths and potential failure points. Computers can leak or otherwise malfunction- however they can also measure what you actually do with considerable precision, and recalculate if something happens and the plan falls apart. Tables on a slate rely on very simple technology less subject to failure, but are comparatively inflexible. Multiple sources of information seem like a good thing. Most important is having an understanding of the issues and the ability to make knowledgeable decisions, i.e. good training.

Reasonable, informed, and balanced advice has no place on scubaboard. Seriously, nice post.

 

[Agility]

My Oceanic computers say that any dive with a first decompression stop much below 70 feet will lock you out. The computer simply doesn't have a viable solution.

Do you have a source for that? This is a genuine question, I am interested.

The Veo 2.0 will switch into Gauge mode as soon as a stop deeper than 21m (70ft) is required.
Veo manual Dok.-Nr. 12-5201-r01 (11/3/09) downloadable from the oceanic site Oceanic Worlwide

 

[flots am]

...and that is a good reason to have a backup.

My point was that the argument that paper produced dive plans don't fail is incorrect, because they require time pieces and depth gauges that are equally prone to failure and equally in need of a backup.

I like beating a dead horse as much as anybody, so I'll just mention that in the above case the dive plan didn't fail, another instrument did. The plan is still just as valid as when it was created. This is quite different from when you need an 80' deco stop and the computer says "Oh crap! Too much deco! You're on your own" (this is apparently possible, as noted in post 54)

However, yes a backup timing and depth device would be good to have, even with a printed plan.

flots

 

[Shearwater]

One of the few references that I can find about the origins of Lockup Mode is from The Proceedings of Dive Computer Workshop edited by Michael A. Lang and R.W. Hamilton. Here is the description of the discussion. (I added the bold to highlight a couple of thoughts.)

"Lockup" mode
The discussion turned to the maximum depth allowed, with concern expressed by
many that the depths allowed are too deep. The values are in the Appendix. Some of the
units go "out of range" or otherwise stop working when the depth is exceeded. This led to
further discussion of the matter of the DC's shutting down when they might be needed
most. One reason for this is that when the diver has "violated" in certain ways, there is no
good algorithm for getting him/her out of that situation with confidence. Example: When
the diver omits a stop on ascent, the computer will see a faster outgassing, but what is more
likely, is that the diver has provoked bubble formation and needs more time, not less, to get
to the surface.

In the cases where the DC's stop computing, they usually continue to provide time
and depth information and it is up to the diver to use that to get to the surface.
A number of suggestions were made about how to handle the violating diver. There
seemed to be agreement that the diver in this situation cannot go unpunished. It was even
suggested that the DC should shock the diver when he violates, or that it should "break" or
go into a lockup mode that requires a $100 repair bill to get it going again. While there was
agreement that the violation should be punished, when to do it and how to do it was not
agreed upon. Another thing that was agreed by most is that we prefer the DC's to continue
to compute for the diver who has violated.

There is a dilemma here, because the focus of the thinking ranged from the novice
student diver to the experienced scientific diver, and the viewpoints seemed to be reflected
in the part of the elephant touched by each blind man. Some wanted the units not to go
deeper that 130 fsw, because that is the "limit" for recreational divers, but the realities are
that the reasons they buy the units is for more aggressive diving. A major theme throughout
this and other discussions is the strong belief that the recreational divers need more and
better training. Whether the DC's should limit their diving was not agreed on at all.

It was pointed out that we were here with concern for the scientific diver, who may
dive to as deep as 190 fsw, if qualified, and his DC should do the job. But scientific divers
also operate under a much higher order of discipline and are far more diligent about
obeying the rules, since there is a lot at stake. Even so, the entire diving community will
note the conclusions of this Workshop.

There was of course a plea to standardize the criteria for the "lockup" mode. The
Workshop did not do that, instead charged the manufacturers with providing some means
of getting out of these violation situations, and to not have the DC stop computing.

Bruce Partridge

 

[Nirvana]

One of the few references that I can find about the origins of Lockup Mode is from The Proceedings of Dive Computer Workshop edited by Michael A. Lang and R.W. Hamilton. Here is the description of the discussion. (I added the bold to highlight a couple of thoughts.)

"Lockup" mode
The discussion turned to the maximum depth allowed, with concern expressed by
many that the depths allowed are too deep. The values are in the Appendix. Some of the
units go "out of range" or otherwise stop working when the depth is exceeded. This led to
further discussion of the matter of the DC's shutting down when they might be needed
most. One reason for this is that when the diver has "violated" in certain ways, there is no
good algorithm for getting him/her out of that situation with confidence. Example: When
the diver omits a stop on ascent, the computer will see a faster outgassing, but what is more
likely, is that the diver has provoked bubble formation and needs more time, not less, to get
to the surface.

In the cases where the DC's stop computing, they usually continue to provide time
and depth information and it is up to the diver to use that to get to the surface.
A number of suggestions were made about how to handle the violating diver. There
seemed to be agreement that the diver in this situation cannot go unpunished. It was even
suggested that the DC should shock the diver when he violates, or that it should "break" or
go into a lockup mode that requires a $100 repair bill to get it going again. While there was
agreement that the violation should be punished, when to do it and how to do it was not
agreed upon. Another thing that was agreed by most is that we prefer the DC's to continue
to compute for the diver who has violated.

There is a dilemma here, because the focus of the thinking ranged from the novice
student diver to the experienced scientific diver, and the viewpoints seemed to be reflected
in the part of the elephant touched by each blind man. Some wanted the units not to go
deeper that 130 fsw, because that is the "limit" for recreational divers, but the realities are
that the reasons they buy the units is for more aggressive diving. A major theme throughout
this and other discussions is the strong belief that the recreational divers need more and
better training. Whether the DC's should limit their diving was not agreed on at all.

It was pointed out that we were here with concern for the scientific diver, who may
dive to as deep as 190 fsw, if qualified, and his DC should do the job. But scientific divers
also operate under a much higher order of discipline and are far more diligent about
obeying the rules, since there is a lot at stake. Even so, the entire diving community will
note the conclusions of this Workshop.

There was of course a plea to standardize the criteria for the "lockup" mode. The
Workshop did not do that, instead charged the manufacturers with providing some means
of getting out of these violation situations, and to not have the DC stop computing.

Bruce Partridge

Thank you for this post, it is very interesting.

Do you know the date of this workshop and which manufacturers attended?

 

[Shearwater]

Thank you for this post, it is very interesting.

Do you know the date of this workshop and which manufacturers attended?

It was in 1988.

You can get the full text including the attendee list by going to the Rubicon Foundation's website Rubicon Foundation and searching the research repository for "Proceedings of the AAUS Dive Computer Workshop"

Bruce

 

[rhwestfall]

Parallel's my experiences of circa 1993 when I was first in the market for a PDC. There were few available in the "mainstream recreational realm" that would give you a decompression schedule.......

And, oh my, were they ever expensive, even if they didn't "do much".....