ABL800 FLEX Reference Manual
2. Amperometric measuring principles
pO
2
electrode,
Continued
The
p
O
2
value for a sample is calculated from the following equations:
Measurement
1
2
2
2
2
K
)
O
Sens(
)
prev
gas2,
,
I(O
upd.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
5 8370
21 712
Sens( O
3.66294
1
2
=
−
+
+
⎛
⎝
⎜
⎞
⎠
⎟
.
.
.
)
01
p
)
upd.1
(sample,
O
upd.30)
(sample,
O
2
2
p
p
−
=
δ
(
)
)
18
upd.
sample,
(
O
2
)
30
upd.
sample,
(
O
)
upd.6
sample,
(
O
)
18
upd.
sample,
(
O
)
upd.30
sample,
(
O
)
upd.6
sample,
(
O
predict
2
2
2
2
2
2
2
p
p
p
p
p
p
×
−
+
−
×
=
where:
I(O
2
,sample,updi) = Current recorded at the
p
O
2
electrode from updating
number
i
with a measurement on the sample.
I(O
2
,gas2,prev) =
Current recorded at the
p
O
2
electrode from the
previous measurement on Gas 2.
Sens(
p
O
2
) =
Relative sensitivity of the
p
O
2
electrode determined
from the last calibration on Gas 1 and Gas 2.
δ
=
Difference between
p
O
2
(sample) from the first and last
updatings.
predict =
Extrapolated value for
p
O
2
.
For
δ
< 2.66 kPa,
p
O
2
(sample) =
p
O
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
p
O
2
(sample) = predict
Continued on next page
2-7
Summary of Contents for ABL800 FLEX
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