RADIOMETER ABL800 FLEX - Page 46

ABL800 FLEX Reference Manual 2. Amperometric measuring principles
pO
2
electrode, Continued
The pO
2
value for a sample is calculated from the following equations:
Measurement
1
2
22
2
K
)OSens(
)prevgas2,,I(Oupd.i)sample,,I(O
upd.i)(sample,O ×
−
=
p
p
Constant K
1
describes the gas/liquid relationship for the electrode.
This constant is defined as:
K 1+0 58370 21712
Sens( O
3.66294
1
2
=−++
⎛
⎝
⎜
⎞
⎠
⎟
.. .
)
01
p
)upd.1(sample,Oupd.30)(sample,O
22
pp −= δ
(
)
)18upd.sample,(O2)30upd.sample,(O)upd.6sample,(O
)18upd.sample,(O)upd.30sample,(O)upd.6sample,(O
predict
222
2
222
ppp
ppp
×−+
−×
=
where:
I(O
2
,sample,updi) = Current recorded at the pO
2
electrode from updating
number i with a measurement on the sample.
I(O
2
,gas2,prev) = Current recorded at the pO
2
electrode from the
previous measurement on Gas 2.
Sens(pO
2
) = Relative sensitivity of the pO
2
electrode determined
from the last calibration on Gas 1 and Gas 2.
δ =
Difference between pO
2
(sample) from the first and last
updatings.
predict = Extrapolated value for pO
2
.
For δ < 2.66 kPa,
pO
2
(sample) = pO
2
(sample, upd.30)
For
2.66 kPa < δ < 5.32 kPa
66.2
)32.5(upd.30)(sample,O)66.2(predict
(sample)O
2
2
δ
δ
−
×
+
−
×
=
p
p
For
δ≥5.32 kPa
pO
2
(sample) = predict
Continued on next page
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