LI-COR LI7200RS - Checking the Span

Zero Gas Regulator
Rotameter
× 100 cc/min
5
10
20
15
25
ter
in
5
10
20
15
25
To Air In
Checking the Span
Check the CO
2
span with a cylinder of CO
2
in air at a concentration that is at the
higher end of the range of concentrations which may be encountered during meas-
urements. For example, a 500 to 1000 PPM cylinder of CO
2
in air, which has been
verified to be accurate to within at least 1% would be a suitable choice for many
applications. Be cautious, as the stated value of the calibration cylinder may be sig-
nificantly different from the actual gas concentration. Set the flow rate to 0.5 to 1.0
lpm. Check the analyzer reading in the software dashboard.
CO
2
Span Gas
Regulator
Rotameter
× 100 cc/min
5
10
20
15
25
te
r
in
5
10
20
15
25
To Air In
For the water vapor span, a convenient standard to use is a dew point generator
such as the LI-COR LI-610. To avoid condensation problems choose a dew point
temperature that is about 3 to 5 °C below the ambient temperature. Also, since
water vapor sorbs and desorbs from surfaces, allow plenty of time for the reading to
stabilize. Set the flow rate from 0.5 to 1.0 lpm. Check the analyzer reading in the
software dashboard.
Section 4. User Calibration
4-3Checking the Span