USL PCA-100 - Manual (Page 6)

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PCA I
NSTRUCTION
M
ANUAL
Ultra Stereo Labs, Inc.
HOW IT WORKS
The Color Analyzer works much like a camera. Light is gathered and integrated
during the exposure time. The exposure time is automatically controlled
according to the amount of light received. Lower light levels require longer
exposures. It is important that the Color Analyzer and the target subject not
move during the exposure period. That period can be from one millisecond
to several seconds.
Measurements should be made while the analyzer is mounted on a tripod in
order to allow time for the exposure to be made. Normally, measurements
are made and readings displayed within a few seconds. With very low light
levels or after a radical change in light level, the analyzer may take up to twenty
seconds to reach a stable set of readings.
The Color Analyzer repetitively scans and reports the results unless the Scan
Button is depressed.
The Scan Button, at the lower left corner of the display, (see Figure 1), is used
to start and stop measurements by the analyzer. The Scan Button allows you
to stop the scanning and hold a set of values for reading. When the scan is
again initiated, it continues until the Scan Button is clicked again.
The small circle in the viewfinder indicates the portion of the target being
analyzed. The viewfinder lens should be capped or shielded when precise
measurements are to be made. Stray light may enter that lens and add to the
readings.
The viewfinder is in focus beyond approximately 35 feet. Closer objects will
be out of focus. The eyepiece lens is adjustable to accommodate differences
in the eyes of users.
Figure 3