Suunto Vyper **SERIOUS BUG** in CNS O2 computation

[jamiei]

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[Genesis]

that dive?

107' on 32% is not particular aggressive... and since it only takes 15 minutes for the alarm to go off, its pretty easy to do.

As for the rest of the issues you claim I've ducked, go back and read the entire thread again - I've done no such thing - and then post your apology.

 

[jamiei]

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[Genesis]

in my SDM log that, if I don't "recalc" it, shows approximately 15 minutes of "actual bottom time" spent between 103 and 107', with three bars on the CNS graph at the end of that time. 32% mix, 1.4 PO2 setpoint. Ascent was my normal conservative ascent, with a total of 11 minutes from departing the bottom until surfacing.

Well within recommendations.

That dive resulted in a display of 30% of allowed CNS loading, when the actual amount of consumed loading is 10% according to the NOAA tables.

Why not all 100%? Because some of the 15 minutes were at 103, some at 104, some at 105, some at 106, and some at 107'. It was close to a square profile dive, but not an exact one (its a small reef with about a 5' relief) There was one excursion for one sample period) to 108, at which point the PO2 alarm sounded, and I immediately ascended the requisite one foot. Most of the time during which this accumulated occurred at 105.

If I had been just a foot or so deeper, it would have toxed me out, even though I was within the MOD for the mix.

An attempt to print this dive shows the END OF DIVE CNS loading, which records as 18%. Interestingly enough, while the REPORT says 18%, the CNS GRAPH says 30% at the end of the dive..... hmmmm...

Here's a link to a screen dump that I put into paint and converted:

showing the cursor on the ~21 minute point in the runtime, and clearly displaying three bars - or 30% CNS loading - on the graph.

BTW, I've got another dive on the same day, to only 76', on 32% mix that upon entry to the water shows me with a 10% loading, and 30 minutes later, at a PO2 of 1.05, has accumulated twenty percent more loading! That's CLEARLY excessive as well, and since I've only seen it once, and it was on the same dive day as the other "excursion", I can only surmise that once you piss off the computer in this fashion and it erroneously racks up the CNS clock it totally hoses its computations for CNS loading frmo that point forward until it desaturates. Again, I'll be happy to print the graphs if you can give me a key sequence that will do it from SDN.

This bug is REAL Jamei, and it is NOT only in the SIMDIVE function.

I'm also not the only person who has recorded this in REAL LIFE. Rich over at SDN has seen the exact same thing on REAL DIVES, not only in the simulator.

Again, the Vytec does not do this; I have dove damn near the same profile on the Vytec and have never replicated it on that computer.

 

[jamiei]

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[jamiei]

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[Genesis]

You violated the MOD for the suunto... I'm sure you got penalized for that. Max means max. You also said it only read 3 bars...You had 5 green bars left... before you even hit the two yellows...

There are 10 bars. Each is 10% of your CNS loading. When you reach 80% it starts complaining. When you reach 100% you are "out".

30% is somewhere between two and three hundred percent of the actual loading for that bottom time and PO2 according to the NOAA tables.

The computer determines your OLF in real time... it doesn't know that you're surfacing and when you did, even though you clearly violated the MOD, it credited you for it. What CNS graph are you talking about? In dive manager? You also got in another deep dive that day for how long? 30 minutes or more? Sounds like you got plenty of bottom time to me.

There were zero CNS loading bars displayed when I went in the water for this dive. Zero. Confirmed by the SDN graph; I checked it before posting this. The CNS graph I am talking about is CLEARLY DISPLAYED in the screen shot I posted. Its on the left side of the screen - clearly displayed.

We all know that suunto is conservative. You claimed that this same dive would give an O2 alarm at 15 minutes and clearly it didn't on your dive to that depth and you went past the MOD.

No, I did not. I said that if I dove to 107' and sat it would give me an O2 alarm at 15 minutes. I did not do that. The average bottom depth on that dive was between 104 and 105'. At the time of the violation (which was for ONE 10 second sample interval, by the way, and can be accounted for by simply swinging the computer back to its position on your hip after unclipping it to check the thing!) the CNS loading showed ONE bar, and did so immediately after the violation as well. If you'd like I'll make some more screen prints to PROVE this. The little dip where I got the beep (which correlates to me undocking the thing to check air and NDL, then reclipping it!) is the ONLY violation.

Look at the actual graph - I did your work for you. There is nothing wrong with that profile.

My actual PO2 was 1.33 at the actual "average" bottom depth (104') and yet I was "charged" three times the actual CNS exposure that I really incurred.

You know the suunto is conservative. You should also not expect the computer to follow your cns clock table. You keep quoted the MOD for the mix and the CNS clock table. You know that the suunto MOD for 32 is 107. Why would you violate it? You know it will penalize you.

It did not penalize me for the 10 second swing of the computer below my body while re-docking it after checking my pressure. If you do not believe me, I will prove it with another screen shot. There was no increase in the CNS graph caused by that momentary violation, as is proven by a look at the graph immediately after it occurred. It also only occurred once. You can clearly see the little "notch" on the profile graph, and the "max depth" picked up is an INSTANTANEOUS depth, and requires no "linger time." BTW, my Vyper is set to 10 second sample intervals, not the default, so its resolution in the log is EXTREMELY high.

The thing is meant to be conservative, thats not a bug. You admit the end of dive CNS loading is only 18% compared to the table's 11%. Sounds like simple safe conservatism to me so far...

No, the CNS loading according to the computer is between 30 and 39% (three bars). The PRINT OUT shows 18%, but the COMPUTER shows between 30 and 39%.

This is not "safe conservatism", its a bug, and tracks within my ability to verify the behavior in the SIMDIVE mode.

 

[Genesis]

You were also clearly at depth for more than 15 minutes, you ascended to 10' then gradually went back down to 20 and then shot blew your final ascent from 15 feet on up.

Yes, I was at depth for about 17 minutes. So?

In short, Horsecrap on the rest of your claims. The final ascent took over one minute from 20', which is WELL within the 30fpm recommended rate. The entire ascent took close to ELEVEN minutes from the bottom to the surface, and other than the "fake" alarm due to surface surge, there were no "jogs" or violations.

There were fairly heavy seas that day. The Suunto computers go into "surface" mode as soon as it sees depth under 3' - even momentarily. The surge at the surface tripped it into surface mode on the final ascent; this is COMMON if you dive in REAL WATER as opposed to a pond somewhere. You might try it sometime; it would be an education for you.

There is no violation on the ascent; I went back to approximately 20' to collect my buddy, who was attempting to avoid both the surface surge and the fish hanging from my waist for HIS stop. Also VERY common with the particular crowd I was diving with that day; my buddy on that dive is one who I dive with all the time and we have a routine for our safety stops when there is significant surface current, as there frequently is around here. We typically leave 6-8' between us on the line when in current, because otherwise we bang into each other - or our fish. Suunto is just fine with any depth between 10-19' for the "safety stop", and so am I, provided that I made a NICE SLOW ascent to that depth (and as you can see from the profile, I DID. SIX MINUTES to cover 100' is about HALF the maximum 30fpm recommended rate!)

A 4' sea produces an 8' swing in water depth from the crest to the bottom fo the trough, and WILL cause any computer that has an "ascent alarm" to show exactly this kind of glitch if you surface in rough conditions. You DO dive in actual open water, do you not?

Second, at no time did I exceed the NDL. I showed you the "point" at the MAXIMUM excursion in terms of both the NDL and CNS displays.... so get off that high horse.

There was nothing wrong with that profile. There was plenty wrong with the CNS loading computation.

If I had been two feet deeper on average, I would have been toxed out.

 

[Genesis]

This from a Vytec....

Just a couple of notes...

This was on 30% Nitrox, thus, the deeper depths. But its the same deal - within a foot or two of the MOD for the deep part of the dive.

Why only one (correct) bar on the CNS loading? Because this profile is from a Vytec on my wrist, not the Vyper.

 

[Aquamaniac]

Karl.
In all seriousness, has this made you re-evaluate using only your tables and doing away with computers?


Dave