Aanderaa 4330 Operating Manual page 53

The temperature in °C is calculated from raw data (RawTemp) by use of a polynomial similar to the above
with coefficients stored in the TempCoef property.
Based on the calibrated phase (CalPhase) and temperature (Temperature) the partial pressure of O
calculated by use of a two dimensional polynomial:
p C t m
∆ = ⋅ ⋅
0
0
where the polynomial coefficients C
in FoilCoefB. The temperature exponents, m
are stored as FoilPolyDegO.
From the partial pressure the air saturation is then calculated as:
( )
AirSaturat ion
where NomAirPress is a property for the nominal air pressure, usually 1013.25 hPa, and NomAirMix is
the nominal O2 content in air, by default 0.20946.
The p (t) is the vapour pressure calculated from temperature by the following equation:
vapour
( .
52
p (t) = e
vapour
If the property Enable HumidityComp is set 'No' the p
The oxygen concentration is finally calculated as:
O 2 Concentrat
*
where C is the oxygen solubility (cm
( )
ln C * =
A + A T + A
0 1 S 2
(
+ S B + B T
0 1 S
where:
T = scaled temperature
s
298

= ln

273

t = Temperature, °C
ph n C t m ph n C
+ ⋅ ⋅ +
0 1 1
1
to C are stored in the property FoilCoefA and C
0 13
0..27
% =
[
NomAir Pr ess −
6690 . 9
- - . * (t+ . )
57 4 681 ln 273 15
t+ 273 . 15
*
C ⋅ 44 . 659
µ
ion ( M ) =
3 3
/dm ) calculated from the Garcia and Gordon equation of 1992:
2 3 4
T + A T + A T + A T
S 3 S 4 S 5
)
+ B T 2 + B T 3 + C S 2
2 S 3 S 0
. 15 − t


t
. 15 +

page 53 of 93
TD 269 OPERATING MANUAL
OXYGEN OPTODE 4330, 4831, 4835
June 2017
t m ph n C
⋅ ⋅ + ... +
2 2
2 27
, are stored as FoilPolyDegT and phase exponents, n
∆ p ⋅ 100
]
( )
p t ⋅ NomAirMix
vapour
(t) will be set to zero.
vapour
⋅ AirSaturat ion
100
5
S
t m ph n
⋅ ⋅
27 27
to C are stored
14 27
is
2
,
0..27