MOD of Scubapro computers at 21%

[lowviz]

...//... It looks to me like the G2 may actually using the 855mb it is measuring ...//...

Wow. Maybe it is the G2...

"The three Atlantic Basin hurricanes (all Category 5) with the lowest pressures on record are Wilma (Oct. 19, 2005, with 882 millibars or 26.05 inches of mercury), Gilbert (Sept. 14, 1988, 888 millibars or 26.22 inches) and the Labor Day Hurricane (Sept. 2, 1935, 892 millibars or 26.35 inches).Sep 8, 2010"

 

[tursiops]

Wow. Maybe it is the G2...

"The three Atlantic Basin hurricanes (all Category 5) with the lowest pressures on record are Wilma (Oct. 19, 2005, with 882 millibars or 26.05 inches of mercury), Gilbert (Sept. 14, 1988, 888 millibars or 26.22 inches) and the Labor Day Hurricane (Sept. 2, 1935, 892 millibars or 26.35 inches).Sep 8, 2010"

Or, the OP might be at altitude.....

 

[lowviz]

Yeah, but altitude and claiming seawater are hard to resolve...

 

[broncobowsher]

Yeah, but altitude and claiming seawater are hard to resolve...

Salt lake city?

 

[lowviz]

I give up.

 

[Dan]

PPO2 / percentage = MOD
1.4 / 0.21 = 6.66666667 atmospheres = which is 5.66666667 metres (the first ATA is free)

You mean 56.7 m?

 

[tursiops]

Yeah, but altitude and claiming seawater are hard to resolve...

He never said he was diving. He might have been just playing with his computer. 855mb is not as high as Denver....for example.

 

[tursiops]

Isn't it so easy. 1 atmosphere is 10 metres. Simple as that.

PPO2 / percentage = MOD
1.4 / 0.21 = 6.66666667 atmospheres = which is 5.66666667 metres (the first ATA is free)

What is it in cubits per squirrel? (Says the Brit!)

you lost a factor of 10.....to get from ata to meters.....

 

[Nick Ruberg]

There is a note on p61 of the G2 manuals:

NOTE: Air (21/0) gives a different MOD than, for example, trimix 21/10. The reason is, the G2 uses a more precise value for the oxygen in the air, which is 20.7%​

It looks to me like the G2 may actually using the 855mb it is measuring -- which is 0.844 ATA -- for its calculations, but is adding in a safety factor (like Suunto does) to calculate the MOD, like 0.3-0.5%, which would allow it to mitigate someone rounding the "wrong" direction in an O2 analysis.

​

Aha. That 20.7% now explains a bit. That is what I backward calculated. Only question now remains why when the barometric pressure was reading 855 millibars (as per the G2) It appeared to use 920 millibars.

also, why 20.7%?

 

[Nick Ruberg]

He never said he was diving. He might have been just playing with his computer. 855mb is not as high as Denver....for example.

Johannesburg, South Africa. We’re pretty high here.