Computer Depth Accuracy

[Jax]

I have two computers and there is a difference in their depth readings. It appears to be a linear spread (deliberately not using the word error). In other words, the spread at 100' is double the spread at 50'. On the surface, they both read zero. The manufacturer specifications says accuracy is, "+/- 1% of full scale." Full scale is 399'. I'm not sure if they meant they can be off by 4' (okay, 3.99') at any point, but that is the way I read it. So at 100', an 8' spread could be in specs. I would have thought the spec would read, +/- 1% of depth. But, that is not my point.

They are the same make, but different models (probably the same hardware though), the same decompression model and database.

Where I see the greatest affect is the NDL bottom time calculation. I generally never push the NDL, so it isn't a factor in my diving. If I did, I would probably go with the shortest bottom time. Up to the time I got the second computer, I compared mine with my depth gauge and accepted the fact they were close, but never the same.

I was just wondering for those who have multiple computers, how close are the depth readings at depth?

For those with a single computer, have you compared it to your buddy's computer at depth? How close were they?

Hey, Seaduced, have you checked for that hidden "altitude" setting? I had to set mine to a known altitude, because it recognizes altitude as well as depth. However, that little footnote was like a single paragraph hidden in the book.

 

[Jax]

Hey, Seaduced, have you checked for that hidden "altitude" setting? I had to set mine to a known altitude, because it recognizes altitude as well as depth. However, that little footnote was like a single paragraph hidden in the book.

PS -- you're welcome to borrow one of mine in Sept.

 

[Seaduced]

PS -- you're welcome to borrow one of mine in Sept.

Hey, Seaduced, have you checked for that hidden "altitude" setting? I had to set mine to a known altitude, because it recognizes altitude as well as depth. However, that little footnote was like a single paragraph hidden in the book.

lol... Could I? Actually, I'm in St Paul this week, I'll check when I get home. I'm ready for a seahorse roundup over Labor Day weekend!

 

[Seaduced]

After 7 dives over the holiday weekend, the older computer is now giving me a low battery warning. I bought a new battery for the older computer, but forgot to take it to Mexico with me.

It sounds like Scott may have the answer. I'll change the battery, but won't be able to dive it again for another two weeks.

 

[bracko]

at the end of the day they're instrumentation and as with all instruments, they do need servicing.

if you've dropped one you may have slightly damaged the diaphram that the pressure sensor works off (if that's the technology it uses, I am assuming that it is...)

all pressure sensors are going to be a bit different as they're calibrated off a master calibration unit, which is calibrated by a master unit, which is.... you get the idea.

sitting at 30m in our advanced course with the hire computers, they were all roughly within a 5% tolerance.