Tolerance of depth accuracy

[gracet]

I have two data plus 2 , and one is reading 3 feet deeper. I seems to be constant difference with depth but I have not verified this. (a 3’ difference at 10’ 20’ and 30’ feet)

What is the visual tolerance when noticing a casual difference in the same reading before deciding to send it in for service ?

I understand that the stated accuracy is “1% of full scale” so that means +- 3 feet at 330. Then that would imply +- 1 at 60 feet. If by chance one gage was high and the other low , then its possible that two gages could be different by 2 feet at 60 but still are within manufacture tolerance.

 

[fppf]

1% of Full Scale means that at any reading the device could be off by 1% of its maximum reading. IE at any depth the gauge could be off by 3.3 feet. So you really could see a maximum of 6.6 feet between the 2.

Now if it said 1% of READING then that means the device can be off by only 1% of what ever the current reading is. IE if it was at 330 feet then it could be off by 3.3 feet, at 33 feet it could be off by .33 feet.

 

[Charlie99]

While a 3' difference is technically within spec, it probably indicates a problem, particularly if you have not always had this reading difference.

I own both a 1 button Data Plus and a 2 button Data Plus 2. The few times I've compared them, they were within 1/2 foot or so -- much better than the spec.

OTOH, I've also had a couple incidents where the computer was obviously off by several feet.

The console the computer is mounted in traps saltwater behind the computer -- the few times I remove the computer it is often wet and salty back there, even several days after the last dive. I suspect that what happens is that salt water crystals on the pressure sensor and causes bogus readings.

A few hours of soaking in 100F water has always restored full accuracy. My suggestion is that you try soaking the computers for a while and see if they start reading closer to each other.

Charlie Allen

p.s. Another basic check on operation without taking it diving is to activate the computer and check NDLs to see if it thinks you are at altitude when you are really at sea level.

 

[visibilityunlimited]

Charlie,
This is why I like reading the posts on Scuba Board. I get to learn some good stuff on equipment care that I can pass on to people thanks

 

[gracet]

Problem dissapeared after a soak and a battery change.