Campbell Scientific AP200 CO2/H2O Atmospheric Profile System - Manual (Page 55)

AP200 CO
2
/H
2
O Atmospheric Profile System
Wait for the value of CO
2
and H
2
O to stabilize. This normally takes one to two
minutes.
Set DO_zero to True. The AP200 will send the commands to the IRGA to do
a CO
2
zero and then an H
2
O zero. While the IRGA is setting to zero, the values
for CO
2
and H
2
O will not be available and NAN (not a number) will be
displayed. This will take approximately 20 s. When the process is complete,
CO
2
and H
2
O will again be displayed. Verify that both of these values are
close to zero.
Press <Esc> to return to the Manual Zero/Span menu.
6.2.3 Do CO
2
Span
At the Manual Zero/Span menu, select Do CO2 Span. This menu guides the
user through the steps to begin flow of the CO
2
span gas and to send the
command to the IRGA to set its CO
2
span.
If seq_ACTIVE is True, set STOPsequence = True to stop the sequence.
Then verify that seq_ACTIVE changes to False.
Check the value of CO2_SPAN_PPM. This is the span value that will be sent
to the IRGA. Ensure that the value is correct for the concentration in the CO
2
span cylinder.
Set valve_number to CO2span (10). Look at the LEDs on the valve module to
confirm the CO
2
span valve is now active.
Check the value of diag_AP200. If it is not zero, a problem in the AP200
system should be resolved before continuing (see Appendix B, AP200
Diagnostics).
Wait for the value of CO
2
to stabilize. This normally takes one to two minutes.
Set DO_CO2_span to True. The AP200 will send the command to the IRGA
to do a CO
2
span. While the IRGA is setting the span, the value for CO
2
will
not be available and NAN will be displayed. This will take approximately 10
s. When the process is complete, CO
2
will again be displayed. Verify the value
is close to the value of CO2_SPAN_PPM.
Press <Esc> to return to the Manual Zero/Span menu.
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