Campbell Scientific AP200 CO2/H2O Atmospheric Profile System - Manual (Page 51)

AP200 CO
2
/H
2
O Atmospheric Profile System
valve_number: this is normally an integer from 1 to 8, indicating which
profile level is being sampled. If the sequence is active, this number should
increment approximately every 15 s (see Appendix F, Valve Sequence Timing,
for details). It may be 9 (Zero) or 10 (CO
2
Span) if the zero/span sequence is
running. The corresponding LED on the valve module should be ON.
sample_flow: The expected value for the sample flow depends on the
elevation (see FIGURE 4-19 and FIGURE 4-20 for details). A significantly
higher flow indicates there may be a leak, whereas a significantly lower flow
indicates the filter or orifice may be plugged.
cell_press: This should be within ± 2 kPa of the pressure setpoint. See
Section 4.2.3, Pump Module, for details.
To access other tables in the CR1000, press <ESC> to go back to the top menu
and then select System Menu. This gives access to all of the system tables. In
particular, the status table is helpful for assessing the status of the CR1000
datalogger (see the CR1000 User Manual for details), and the public table
shows the value of each public variable as it updates in real time. See
Appendix C, Public Variables, for details on the variables in the Public Table.
5.6.2 Checking Status Remotely
If the system is configured with an NL115 and a network connection is
available, the AP200 can be checked remotely by connecting a PC via
LoggerNet (other software is also available that provides some of the
functionality of LoggerNet – see Section 4.1.5, Support Software). LoggerNet
may also be used on-site with a serial cable connected directly to the
datalogger. All of the variables listed in the on-site access can be checked in
the Public table. For thorough performance verification, each of the variables
in the public table can be compared to their normal values. See Appendix C,
Public Variables, for details.
5.6.3 On-site System Checks
There are several important checks that can be done on site, during initial
installation, and during routine site visits to retrieve data and maintain the
system.
NL115 or CFM100: Check that the status LED is blinking red periodically,
indicating that data are being written to the card. See the NL115 or CFM100
manual for details.
Sample pump: Listen to the sample pump which should be making a steady
hum. A slight change in pitch is normal when switching between the
calibration (zero/span) and profile sequences, but a sustained oscillation in the
pitch indicates a problem. See Appendix B, AP200 Diagnostics, Bit 4.
Enclosure humidity: Check the humidity indicator card on the door of the
AP200 system enclosure and replace the desiccant when the humidity reaches
50%. See Section 7.2, Enclosure Desiccant.
Zero and span cylinders: Check the cylinder and regulator outlet pressures.
It is recommended to log the tank pressures at each site visit and note the trend.
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