4ster

The formula for a linear cell:
Air_mV / .209 = X / .98
where X is the mV in O2 and .98 is the O2 purity of the test gas.

(This is what is neat about this community, I asked Bruce at Shearwater essentially the same question about a year ago when I was fitting a GF to my Dolphin, he kindly wrote back with a few suggestions on how to check linearity and the above formula. You will find this formula in other posts about linearity testing here.)

The idea for the spreadsheet was from another post here (but I can't remember who to credit), I adapted the poster's idea for my use. I wanted a single laminated sheet to check linearity to 1 ata O2. If you want, pm me your email address and I can send my excel sheet if that would help.

Since cells are seldom perfectly linear I wanted a quick way to judge just how non-linear a reading was. The -3, -1.5, 1.5, +3 refer to percent divergence from perfection.

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Steve
"My problem is that I have trouble reconciling my gross habits with my net income." Errol Flynn