Atmos 2 sample rate.

WetFatCat · May 17, 2007

Aeris Atmos 2 sample rate could be set to different time or depth intervals.
What is the difference? What are limitation of less sample rate?
I suppose that with 15 seconds rate twise less data is stored than with 30 seconds one. But how many it twice less or twice more? How many data slots computer could store?

And the general question (at last). What is a reasanoble setting to cover dive profile without unnecessary redundancy?

Thanks.

aquaticmatt · May 18, 2007

Think of your sampling rate as a snapshot of your dive. If you have it set at 30 seconds, then your computer will record your data every 30 seconds. If you have it set at 2 seconds, then your computer will record your data every 2 seconds, thus using more of you computers memory.

As far as a reasonable setting to cover your dive, Most people set it at either 15 or 30 seconds. This gives you the ability to do multiple dives and not lose your data before you download the dives to your PC.

Hope this helps!

Marek K · May 18, 2007

I just bought an Atmos 2, and haven't dived with it yet.

But looking at the user's manual (p. 41), it stresses that the sampling rate only has to do with how often data is gathered for download to a PC. Nothing to do with how data is real-time displayed, or logged internally.

Um, what do you mean by "different [...] depth intervals"?

The factory pre-set is for 30 seconds. I would imagine that's a reasonable value, unless for some reason you needed more resolution downloaded to your PC.

In addition to taking up more space in the Atmos 2's memory, I'd guess that a more-frequent sampling rate might also run down you battery faster. (?)

--Marek

WetFatCat · May 18, 2007

So I'd like to know how many data samples may be stored in Atmos 2 memory. It could give the idea about how much dive time may be traced with different rates.
Let's say I'm goung to vacation and it could be 20+ diving hours. Does Atmos 2 have enough memory to store 20 hours snapshot with 15 seconds rate? And with 2 seconds? I'd like to trace all dives, but I don't like to get a laptop.

Another question is what happens when memory is filled. Does Atmos delete the whole snapshot of the oldest dive or replaced oldest data slots one by one?

The manual says: "the Sampling Rate can be set to values of 2, 15, 30 or 60 (seconds), or 2, 5, 10 feet (.5, 1.5, 3 meters)."
For me it means that Atmos writes data to a new slot every N seconds or every time when depth changed by K feet. Two different criterias.

Marek K · May 18, 2007

Ah, you're right! I completely overlooked that reference to a depth-related sampling rate. I guess you can set it to either time or depth, and the pre-set is to 30 sec.

I understand you do want to download to a PC after a long dive trip, and need to know how many dives the memory would hold at a given sampling rate? Sorry, I can't help you there. I don't plan on ever downloading. All I know is that the Atmos 2 will hold an internal log of the last 24 dives, and that's more than I need (stubby-pencilling data to a paper logbook at least once a day).

Considering that there aren't a lot of folks who even drag a laptop around with them on a dive vacation, I'd guess the 30 second pre-set would allow for the number of dives you're talking about. But that's just a SWAG.

crpntr133 · May 18, 2007

If I am thinking right there is another thread that someone from Aeris posted some times on the different settings.

Doug Krause · May 18, 2007

Estimated memory capacity for each sampling rate setting:

60 Seconds
50 Hours

30 Seconds
25 Hours

15 Seconds
12 Hours

2 Seconds
2 Hours

bperrybap · May 18, 2007

The PC s/w doesn't work properly with depth based sampling.

In depth based sampling samples are stored in dive computer
when the depth changes the selected amount.
When in this mode samples are not stored on regular and even
time intervals. Each sample does have a timestamp on it but
they do not occur on regular intervals. For flat or slow moving
profiles this storage method can use quite a bit less memory.

The PC s/w doesn't appear to use the timestamps. It
appears to calculate average depth by averaging all depths
of all the samples. This calculation only works when the
samples are evenly spaced in time which in depth based
sampling they are not.
So in Depth based sampling the PC s/w will miscalculate the
average depth.

--- bill

Marek K · May 18, 2007

WetFatCat:
Let's say I'm goung to vacation and it could be 20+ diving hours.

Marek K:
I'd guess the 30 second pre-set would allow for the number of dives you're talking about.

Doug Krause:
Estimated memory capacity for each sampling rate setting:
[...]
30 Seconds
25 Hours

Hey, I guessed right! *whew*

Do I win anything?

WetFatCat · May 18, 2007

Great thanks for the valuable invo.

Marek, you are the man!

Dmitriy.

Atmos 2 sample rate.

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lost, even with a compass

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