PROBE BUDDY – USER MANUAL
Page 17 of 27
UPC_MAN013_R7
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3 PROCESS FORMULAS
There are three main process formulas available: carbon, dew point, and oxygen. The carbon
and dew point formulas assume an endothermic atmosphere in equilibrium.
Carbon Formula
The primary factor effecting this process is the amount of carbon monoxide, normally assumed
to be 20%. This calculation is accurate for endothermic atmospheres operating in equilibrium,
but the CO correction variable allows for adjustment of the carbon calculation based on actual
%CO readings or results from material tests. The PROBE BUDDY’s sensor millivolt output
simulates the signal from an in-situ zirconia sensor. The T/C output simulates the integrated
temperature T/C in the oxygen sensor.
Tk
Eo
Tk
Eo
e
CO
e
Carbon
043102
.
0
/
)
786
(
043102
.
0
/
)
786
(
))
/
20
(.
*
5
.
4728
(
*
102
.
5
%
−
−
+
=
Where: Tk = Sensor temperature Kelvin
Eo = Sensor millivolt output
e = natural log
CO = Variable CO%
CO is a user variable that can be changed in the SETUP / CALC / CO/H2 parameter. The
default for this variable in 0.20. The .20 in the numerator of the CO ratio assumes 20% in a
normal endothermic process.
Test Case 1:
Temp = 1600°F = 1144.261K
mV = 1050
CO = 0.20
%Carbon = 0.2182
Test Case 2:
Temp = 1700°F = 1199.817K
mV = 1155
CO = .17
%Carbon = 0.9397
The displayed %Carbon value will be rounded up to X.XX. Displayed value range is 0 - 2.55%.
Dew Point Formula
The primary factor effecting this process is the amount of hydrogen, normally assumed to be
40%. This calculation is accurate for endothermic atmospheres operating in equilibrium. The
