LI-COR LI-830, User Manual

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Section 2. Configuring the gas analyzer
Using alarms
The alarms can be set for CO
2
or H
2
O (in the LI-850). In either case, each alarm
features an activation level and a deadband. The low alarm is activated if the meas-
ured concentration drops below a threshold. The deadband is the range above the
low level over which the alarm remains activated. The high alarm is activated if the
measured concentration exceeds a threshold. The deadband is the range below the
high level over which the alarm remains activated.
Elapsed Time
C
O
2
C
o
n
ce
n
tra
ti
o
n
,
p
p
m
300
400
700
600
Low Deadband
High Deadband
500
Low alarm
activated when
CO2 <300 ppm
On = 300
Low alarm
deactivated when
CO2 >350 ppm
Deadband = 50
High alarm
activated when
CO2 >700 ppm
On = 700
High alarm
deactivated when
CO2 <600 ppm
Deadband = 100
Figure 2-2. An alarm is triggered when a concentration is outside of a threshold. For
example, the low alarm is activated if the concentration drops below 300 ppm and is deac-
tivated when the concentration rises above 350 ppm. The high alarm is activated if the
CO
2
concentration exceeds 700 ppm. The alarm is deactivated when the concentration
drops below 600 ppm.
Figure 2-3. The
Alarm Settings
window is where you configure alarms. The settings shown
here will give the behavior shown in Figure 2-2 above.
2-8 Using the LI-830 and LI-850 Gas Analyzers