Campbell Scientific AP200 CO2/H2O Atmospheric Profile System User Manual
Page 99
Appendix F. Valve Sequence Timing
•
Select inlet 1 to allow at least 10 s extra equilibration time. This
allows the humidity in the tubing and IRGA to equilibrate before
restarting the profile sequence.
As shown in TABLE F-4, this minimum timing adds up to 170 s for the
zero/span sequence. The timing parameters are adjusted as needed to equal a
multiple of the profile sequence cycle time. For example, if there are 8 levels
used, the profile cycle time is 120 s. Because this is less than the 170 s
required, it is doubled to 240 s. Extra equilibration time is added to each step to
make the zero/span sequence equal 240 s. If there are four levels used, the
profile cycle time is only 60 s. Three profile cycles times are used to give 180 s
for the zero/span sequence.
TABLE F-4. Timing for Zero/Span Sequence (setting the IRGA)
Number
of Levels
Profile
Cycle
Time (s)
Measure
CO
2
Span
Time (s)
Measure
& Set Zero
Time (s)
Measure
& Set CO
2
Span
Time (s)
Equilibration
Time (s)
Zero/Span
Time (s)
Minimum
30
70
60
10
170
8
120
40
100
70
30
240
7
120
40
100
70
30
240
6
90
30
70
60
20
180
5
90
30
70
60
20
180
4
60
30
70
60
20
180
Each time the zero/span sequence is run, five records will be added to the
SiteAvg and CalAvg tables:
•
CO
2
Span tank before setting zero or span
•
Zero tank before setting zero or span
•
Zero tank after setting zero
•
CO
2
Span tank after setting zero
•
CO
2
Span tank after setting span
F-5