LI-COR LI-7815, Instruction Manual

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Section 4. Software overview
Diagnostic log
Download Diagnostic Log
is to download a dataset that includes detailed per-
formance information. This option should be used in consultation with LI-COR
technical support in order to resolve performance issues. Diagnostic log files can be
very large, (hundreds of MB, depending on the time and date range), so we recom-
mend that you constrain the dates to a narrow time window when downloading a
diagnostic log.
Performance monitor
The central portion of the window provides more details about the instrument per-
formance.
l
Phase Error
is an indicator of the symmetry of cavity modes. During normal
operation the needle will be within the green part of the dial.
l
Cavity Pressure
is measured in the optical cavity. The instrument operates
around 40 kPa typically. If the values are colored red, that indicates that the
instrument is unable to regulate the cavity pressure. Normally this value is
within 1 kPa of the setpoint.
l
Phase Pressure
refers to the pressure for the phase adjuster volume. If red, the
instrument is unable to regulate the pressure to get optimal phase adjustment.
Normally this value is within 1 kPa of phase pressure setpoint.
l
Fit Residual
is the difference between the raw spectra and the best fit spectra
which generates the measured concentrations. If the residual is red, it indicates
that the instrument is unable to process the data properly and that the con-
centrations are not being reported accurately. Data will be flagged in this case.
4-12 LI-7815 CO₂/H₂O Gas Analyzer