OPHIR vega User Manual page 42

indicating that zoom is engaged. Now press the "Zoom"
button again to return to the unexpanded bargraph
display.
4.4.2.2. Offset
The offset function subtracts background from the signal.
If the ambient environment has a thermal background, so
that the Vega shows a nonzero power reading even when
there is no laser, you can subtract the background using
the zero function. For example, the Vega display reads
0.1 Watts when the laser is blocked, and 20.5 Watts with
laser power applied. In this case, the true power is 20.5 -
0.1 = 20.4 Watts. To subtract the background, press the
"Offset" button while the laser is blocked. The Vega will
now read zero, and the 0.1 Watt background will be
subtracted from all subsequent readings. The laser power
reading will thus be 20.4 Watts.
When "Offset" is engaged, the legend is highlighted. To
cancel, press "Offset" again. If the "Offset" is engaged,
and you wish to subtract out a new value of the
background, press "Offset" twice. The first press will
cancel the old value, and the second will activate a new
value. If you suspect that the Vega has a permanent zero
offset, then disconnect the sensor while it is in the power
measurement mode. If the Vega still
shows a similar offset even when the sensor is not
connected, the instrument's internal zero should be
reset. See Section 3.5.5.
4.4.2.3. Tune (See Figure 4.1 )
The Tune function, an exclusive Ophir feature, makes
adjusting your laser to its maximum power easier than
ever before. Unlike a bargraph or needle display, this
display shows graphically what came before as well as
the current reading and the trend. This allows you to
determine if you have reached maximum power.
The screen is completely autoranging. Therefore, as
soon as the cursor goes over the top or under the bottom
edge of the display, it re-scales to put the cursor back to
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