I dive with two computers, each displays different tank pressures ?

[NAM001]

Sounds like a bunch of technical stuff. just get a tank from the shop and put your reg on it and then put the shop whip on it . compare the shop fill gage with your 2 readings. unless the shop reads right in the middle you should be able to find out what you want. I suspect that the analog gage is going to be correct or more correct than the pressure sensor. heck test against some of your buddies regs and see what matches. I would think you would already know which is bad as you get a tank filled to 3k and your 2 gages read wither 2700 or 3300 and the other reads 2950. Whether the tank actually has 2950 or 2980 is moot. That will check the upper end of the gage. when you get to the end of your tank say 500 psi check it against your buddies gages with them on your tank. the 500 psi tank should read near 500 on one of your gages and the other will read perhaps 200 or 800 psi. The low end of the gage is the range that has to be accurate as no one dies from too much air in the tank. Any time I had a gage error it was from the xmitter on the AI unit. BTW the error was always 300#. Weird but with 3 different ai sensors going bad over the years the error was always 300#. I don't remember in which direction the error was however.

 

[Scared Silly]

Segal's law is an adage that states:
"A man with a watch knows what time it is. A man with two watches is never sure."

 

[The Chairman]

Dunno about accuracy but go by the cobalt because if you're down to 0 and it's wrong you'll have a reserve. If you go down to 0 by oceanic and it's wrong, you're OOG.

I would do this. It makes the most sense.

 

[divad]

I would do this. It makes the most sense.

Not if the Oceanic is just wronger.

 

[undrwater]

This one goes to 11?

 

[scubadada]

I dive an AI Oceanic VT3 primary and a Geo2/SPG backup. The analog guage has always read about 100 psi higher than the computer, full range. I don't know which, if either, is "correct". I've never been below about 250 psi on the computer.

 

[Littlerayray]

I would only use an AI comp as a guide
I would still keep an analogue spg since they are accurate

 

[scubadada]

I would only use an AI comp as a guide
I would still keep an analogue spg since they are accurate

I'm not really sure which of mine is "more correct", they're close though

 

[dmaziuk]

I would do this. It makes the most sense.

I would do what RonR says and have the cobalt's sensor calibrated. Sensors in AI transmitters tend to be not user-calibrateable -- there's usually not enough supporting hardware in there -- but if it is off it's worth talking to tech. support about it.

There's no inherent reason for these sensors to be less accurate than a bourdon tube, in fact, quite the opposite: they should give more linear response over wider range of pressures. The idea that analog gauge is "more accurate" in general is just FUD.

 

[dmaziuk]

Not if the Oceanic is just wronger.

They could also be non-linearly wrong and their wrongs cross at some point...