History behind Dive computer error mode

[ballastbelly]

My suunto will lock into an error mode if you are in violation of its depth instructions for decompression for more than 3 min.

I presume other brand DCs also give up on you if you violate their instructions.

When did this become the defacto norm? Essentially the DC is giving you an on screen Darwin award instead of using the computer power available to interpolate a best effort solution.

If I ended up in deco trying to save a buddy, & later messed up a 12m deco stop, would i expect even my DC to snobishly abandon me at that moment too? Thx
B

 

[Dr. Lecter]

My suunto will lock into an error mode if you are in violation of its depth instructions for decompression for more than 3 min.

I presume other brand DCs also give up on you if you violate their instructions.

You presume incorrectly. Shearwater computers (indeed, any tech computer worthy of the name) will not lock you out, nor will Atomic computers.

 

[boulderjohn]

I believe (not sure) that the thinking is that if you violated their algorithm by that much and somehow managed to live, you should stay out of the water for two days to be sure you have sufficiently recovered. Several other computers have a similar approach.

As Dr. Lecter correctly pointed out, others will continue to operate under the theory that you made a decision for one reason or another to do something other than what they suggested and would still like to have a functioning computer.

 

[RonR]

My suunto will lock into an error mode if you are in violation of its depth instructions for decompression for more than 3 min.

I presume other brand DCs also give up on you if you violate their instructions.

When did this become the defacto norm? Essentially the DC is giving you an on screen Darwin award instead of using the computer power available to interpolate a best effort solution.

If I ended up in deco trying to save a buddy, & later messed up a 12m deco stop, would i expect even my DC to snobishly abandon me at that moment too? Thx
B

The Atomic Cobalt doesn’t do this, there is no “lock out” mode- and it is very much a recreational computer.


A deco violation in the Cobalt is actually determined by a kind of mini-algorithm, it’s not just a set number of minutes away from a stop, but either a percentage of the stop time or the depth or both that triggers the violation alert. But the Cobalt continues to recalculate a best fit schedule to the surface as long as it is possible, even in a violation. It will display an ugly yellow banner where the tissue loading graph normally is that warns you the schedule may not be valid, but it will leave it up to the diver to decide if the violation was relatively trivial or not. You will get the warning for 24 hours, but the computer will continue to function normally otherwise.


Deco is a fuzzy gray area, not a binary switch. Obviously we agree that having your computer give up on you is not helpful.

Ron

 

[KeithG]

When did this become the defacto norm? Essentially the DC is giving you an on screen Darwin award instead of using the computer power available to interpolate a best effort solution.

B

i claim this feature is directly related to the manufacturer having more lawyers than engineers on staff...
if the computer keeps "working" then you can continue to dive with it. so it is now the manufacturers fault (not mine!)

same reason why the US will never have autonomous vehicles - who do you sue?

---------- Post added July 25th, 2014 at 10:12 PM ----------

p.s. they generally do not lock out until you reach the surface. they help you finish this dive, but refuse to participate in another one right away.

 

[sharkbaitDAN]

I'm a little confused about your stated scenario. I was just looking at my D6 manual to see what it says, and you only get locked out for being shallower than the ceiling for 3mins or more. If you are below, deco will either increase or decrease depending on depth.

Second, concerns a potential ceiling of 12m using a Suunto dc. How deep and for how long would you have to be down for this to occur? I've had Suunto computers go into deco before, I've never had a ceiling deeper than 3m. If you're referring to the 12m deep stop, you can violate that all you want, it's not a ceiling, and therefore will never go into error mode for a violation. If you can't correct an issue at a 3m stop within 3 minutes, you probably are better off on the surface and on O2.

As to the rationale, I agree with people above, liability probably is what keeps this on the computer. However, the Suunto off gassing algorithms were simply never designed for decompression diving, and the only way to get into the error mode is to violate the computer's rules 3 times. First for violating NDL, second for ascending above ceiling, and third for not descending within three minutes.

 

[ballastbelly]

....
Second, concerns a potential ceiling of 12m using a Suunto dc. How deep and for how long would you have to be down for this to occur? I've had Suunto computers go into deco before, I've never had a ceiling deeper than 3m. ....

to clarify i am a novice diver, and the only experience i have in deco is on divepal
but i did trigger the error text 'Er' at a 9m ceiling (following a uncontrolled ascent violation after 40min at 50m using twin tanks on the simulator).

OTOH i have been puzzled by this 3 min clip by enthusiasts where a gopro was mounted to a suunto and dropped with an anchor

Gopro hero 3+ a 36 metros con sunnto zoop en isla de tabarca - YouTube
as they started to pull it up at 15min dive time it shows a 30m ceiling (ffwd the youtube clip to 2 min 32sec)
suddenly at 16min dive time (Youtube 3min 06 sec), the anchor surfaces to around 0.6m (no error is shown- did they swap the suunto with another? am i missing something?)

do you know of other websites where i can find similar experiments? thx

 

[sharkbaitDAN]

You are kind of making my point. I would never count on a suunto for efficient decompression for a 50m/40min dive, if for no other reason than best practices dictate trimix and a separate decompression gas. You would have to plan that dive, and it does not sound like you currently have the tools to allow you to do that safely.

As to the video, it never shows the computer in decompression mode. It does show a 3m ceiling due to a fast ascent rate, and the mandatory safety stop icon. This can be ignored without triggering the error mode because mandatory decompression was not omitted. The mandatory safety stop, if ignored, will drastically cut down your NDL times for subsequent dives over the next 12-24 hours. I do agree that it is confusing that the same ceiling icon is used for both safety stops and decompression, but there are other differences in the screen to tell you which mode you're in (stop, no dec time, or asc).

 

[KenGordon]

As to the rationale, I agree with people above, liability probably is what keeps this on the computer. However, the Suunto off gassing algorithms were simply never designed for decompression diving, and the only way to get into the error mode is to violate the computer's rules 3 times. First for violating NDL, second for ascending above ceiling, and third for not descending within three minutes.

Going past the NDL on a Suunto is certainly not a violation of the computer's rules. That is what it is for, just because some happen to want to dive within NDL does not mean the rest of their customers do. In the UK we regularly do mild deco dives, 5 or 10 minutes of mandatory stops is not remarkable at all, getting locked out is remarkable and will cause questions to be asked. Suuntos are very popular with those diving like that.

I use a Zoop as a backup computer and a Helo2 as a main computer. For deep dives I cut tables with a PC as my limits. Since the Zoop (being a single gas computer and me using multiple deco gases) has no idea what I am really breathing it gets quite upset, but before that it certainly shows me a ceiling well below 3m. I recall a training dive when it was showing a 7m ceiling when I was on my 6m stop - I may pay more attention in future to see when it finally sulks. What I really want it for is depth and time so I can always use my deco plan if the Helo2 fails.

Ken

 

[Dr. Lecter]

for a 50m/40min dive . . . best practices dictate trimix and a separate decompression gas..

I don't know if you're lying, or simply ignorant, but this statement is false. Kindly stick to whatever it is that you know.