Campbell Scientific TGA100 Trace Gas Analyzer Manual - Manual (Page 32)

3.4.5 Detector Video
This next menu column, labeled “DET VID”, is used to select the display mode of the processed detector data in the
two bottom-right displays. The display mode may be selected either by pressing the corresponding Quick key or by
highlighting the selection using the <up/down arrow> keys and pressing <enter>. Each option is discussed below.
Magnify displays the reference and sample transmittance, scaled to the maximum and minimum of the data used in
the concentration calculation (i.e., the data between the vertical dashed lines).
MaXdisp displays the reference and sample transmittance, scaled to the maximum and minimum of all of the data
(including the zero, high, and omitted data).
DeTrend display mode is similar to the Magnify display mode, but the data have been detrended by fitting a line to
the data and dividing by this line.
Folded display mode is similar to the Magnify display mode, but the data have been averaged with a reversed copy
of the data to make them symmetrical about the center of the spectral scan (the center vertical dashed line).
Absorbnc mode displays the absorbance of the (folded) data instead of the transmittance.
3.4.6 Functions
The FUNCTION menu allows the user to turn functions on or off, and displays their status. The functions are indicated
as either on i.e. [on] or off i.e. [ ]. The functions may be toggled on/off either by pressing the Quick key or by
highlighting the selection using the <up/down arrow> keys and pressing <enter>.
LInelock[ ] automatically adjusts the laser DC current to keep the reference absorption line minimum in the center
of the spectral scan. The line lock function must be on during normal operation.
DataColl[ ] turns 10 Hz data collection on or off. This function must be on to save the concentration data to a file.
Gradient[ ] turns gradient measurements on or off (see section 5.1).
Laser On[ ] turns the laser on or off. The laser must be on for normal operation.
SiteMean[ ] turns site means measurements on or off (see section 5.2).
OffsetGn[ ] turns automatic control of detector gains and offsets on or off. This function is normally on during
routine operation.
DualRamp[ ] turns dual ramp mode on or off.
SCroll [ ] toggles graphs 1 and 2 between scroll and retrace mode.
3.4.7 Graph Selections
This field is used to select the variable to be displayed in graphs 1, 2, 3, or the detector graphs. When this field is not
selected, its heading reads “GRAPH SELECT” with a blank area below. When it is selected, its heading will read either
“GRAPH 1”, “GRAPH 2”, “GRAPH 3”, or “DETECTORS” depending on which menu is selected using the left arrow
or right arrow keys. The “DETECTORS” menu is available only if dual ramp mode is on. The options for the graph
selected (1, 2, 3, or DETECTORS) will be displayed below the heading, and the border of the graph selected will be
highlighted.
There are up to 65 options available for display in Graphs 1, 2 or 3. These options are displayed one page at a time, and
the user may view the other options using the <up/down arrow> keys, the <PgUp, PgDown> keys, or the
<Home/End> keys. Use the <up/down arrow> keys to scroll up and down one item at time. When the top or bottom
of the list is reached, pressing the <up/down arrow> key one more time will display the next page of options. Pressing
<PgUp, PgDown> keys will also display more options. The <Home/End> keys will move you to the beginning or the
end of the list, respectively. The complete list of display options is found in Appendix A.
In dual ramp mode, the “DETECTORS” menu becomes available, allowing the user to select which ramp (A or B) is
displayed in the detector signal graphs in the lower left corner of the real time screen and the transmittance graphs in the
lower right corner. In single ramp mode, the average of ramps A and B is always displayed.
describes the
options available in the “DETECTORS” menu.
Table 4
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