LI-COR LI7200RS, Инструкция по эксплуатации

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Zero H
2
O
Now is a good time to check and set the H
2
O zero, if needed.
8 Click the
Manual
tab, and note the present value of Z
wo
(H
2
O Zero).
Wait for the H
2
O reading to stabilize in the dashboard (3 or 4 minutes). The
Gas
Stability
flag will turn from a red ‘X’ to a green flag when it is OK to perform the
calibration.
9
Click the
Zero
tab, and click
Zero H2O
. Note the new value of Z
wo
(typically between 0.9 and
1.2).
Span CO
2
10 Flow a CO
2
span gas through the optical path at 0.5 to 1 liter/minute.
11 Click on the
Span
tab and enter the mole fraction in the ‘Span gas concentration’ field.
12 When stable (1-2 minutes) click
Span CO2
.
Click the
Manual
tab and check the new CO
2
Span value S
c
(typically 0.9-1.1).
Span H
2
O
13 To set the H
2
O span, flow air of known dew point at about 0.5 to 1.0 LPM.
To prevent condensation, use a dew point temperature several degrees below the
ambient temperature.
14
Click the
Manual
tab, and note the present value of the H
2
O Span value S
w
.
Go back to the
Span
tab and enter the span gas dew point temperature in the
Dew
point temperature
field.
15
Observe the H
2
O dew point in the dashboard and wait for it to stabilize.
The
Gas Stability
flag will turn from a red ‘X’ to a green flag when it is OK to per-
form the calibration. This may take up to 15 or 20 minutes .
16
When the reading has stabilized, click
Span H
2
O
.
Click the
Manual
tab again and note the new H
2
O Span value S
w
(typically 0.9-
1.1).
Section 4. User Calibration
4-7 Zero H2O