Marathon OXYMITH TRANSMITTER F200060 User Manual
Page 11
Page 8 of 23
11/14/2006
Rev. 14
Process Variable Calculations
The transmitter has a selectable process calculation for percent carbon, percent oxygen, or
dewpoint. The following equations are used to derive these values;
Percent Oxygen
20.95
%O2 = -----------------------
e
(E/0.0215*Tk)
Where: E = probe millivolts, Tk = probe temperature in degrees Kelvin.
The 20.95 is the %O2 in air.
Percent Carbon
e
((E-786)/(0.043102*Tk))
%C = 5.102 ---------------------------------------------------
(29*PF + 400)+
e
((E-786)/(0.043102*Tk))
Where: E = probe millivolts, Tk = probe temperature in Kelvin, and PF is the process
factor.
Dewpoint
4238.7
DP = -------------------------------------------------------------------- - 459.69
6.281216 + log((29*PF+400)+(E-1267.8)/(0.05512*Tr)
Where: E = probe millivolts, Tr = probe temperature in Rankin, PF is the process factor,
and DP is the dewpoint in Fahrenheit.