Aqualung i300c Average Depth Calculation Issues?

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

dannysporea

Registered
Messages
47
Reaction score
6
Location
Fairfax, VA
# of dives
100 - 199
I think there is a problem in the firmware of the i300c dive computer on how it calculates the average depth for the dives... and the dive log shows the wrong average depth. Here is an example for my last 6 dives:

Code:
#    Start Time   End Time     Date      Pre Dive Surface Interval    Max Depth (m)    Dive Time    Average Depth (m)
6    13:49        14:28        06-Sep    00:22                        8.9              33           0.6
5    12:43        13:27        06-Sep    23:50                        7.4              43           0.9
4    11:51        12:48        05-Sep    00:31                        12.9             57           2.7
3    10:29        11:19        05-Sep    21:52                        21.9             50           5.6
2    11:40        12:32        04-Sep    00:28                        15.9             52           5.5
1    10:26        11:11        04-Sep                                 21.3             44           16.8

The only accurate average depth is for dive #1... all the rest are wrong until the dive numbering is reset again, when the first dive is correct and the rest appear as if the computer includes the surface interval or some other values in the average making the average go down and down, regardless of the actual recorded maximum depth and dive profile.

For the example above, the correct average depth should have been as follows:

Code:
#    Average Depth (m)
6    5.1
5    4.7
4    9.3
3    16.4
2    10.1
1    16.8

Is this a bug in the firmware or I am not understanding something correctly on how the computer should calculate the average depth for each dive?
 
Did you use subsurface to check what it says compared to what the watch reports? I just checked and subsurface matches the watch.
 
How are you calculating average depth to know that the value the watch reports is wrong?
 
The average depth in the first table is what the watch shows in the log. The average depth showed in the second table is what Subsurface calculates based on the dive profile. Only the first dive average depth matches Subsurface, all the rest are way lower.
 
Subsurface calculates the average depth simply based on the samples which are taken at discrete intervals.
A dive computer can (and I believe some do) internally take more frequent measurements to create its average depth value. So having that diverge from what Subsurface shows doesn't mean it's wrong.
 
Subsurface calculates the average depth simply based on the samples which are taken at discrete intervals.
A dive computer can (and I believe some do) internally take more frequent measurements to create its average depth value. So having that diverge from what Subsurface shows doesn't mean it's wrong.

My dive computer is set at 2 seconds interval, the most granular sampling rate available, and the values are way off between the measurements. The computer calculates 5.6 m on a dive to a maximum 22 m which according to the dive profile the average should have been 16 m (3 times more than what the computer calculates).
 
https://www.shearwater.com/products/perdix-ai/

Back
Top Bottom