PHOTO RESEARCH SpectraDuo PR-680, Руководство пользователя

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PR-680/680L User Manual
20
S
ETTING THE
I
NSTRUMENT
S
ENSITIVITY
R
ANGE
The PR-680/680L has two Adaptive sensitivity ranges – Standard and Extended. You can set which range
the Adaptive Sensitivity algorithm uses. For Standard sensitivity, the exposure time range is 6 ms to
6,000 ms. For Extended sensitivity, the exposure time ranges from 6 ms to 30,000 ms thus extending the
sensitivity. To set the Sensitivity range:
1. Make sure Adaptive is set to Enabled.
2. Touch the
▼
or
▲
icon in the Sensitivity field to toggle between Standard and Extended.
S
ETTING THE
M
EASUREMENT
S
PEED
The total time needed to complete a measurement is certainly an important issue. This feature can help
speed up measurements by changing the way the Adaptive Sensitivity determines when a measurement
is completed. In the
Fast mode, the total measurement time will be approximately halved. In 2X Fast,
total measurement time will be reduced approximately 4 times and in 4X Fast by approximately 8 times.
Caution: To insure measurement quality (accuracy and repeatability) is not adversely
affected while using one of the optional measurement speeds ( Fast, 2X Fast or 4X
Fast) , we strongly recommend running tests for accuracy and repeatability prior to
using these modes for critical measurements. This is most easily achieved by
comparing results with measurements made in the
Normal mode.
To select a Speed mode:
1. Make sure Adaptive is set to Enabled.
2. Touch the
▼
or
▲
icon in the Speed field to toggle between Normal, Fast, 2X Fast and 4X Fast .
S
ETTING THE
SYNC M
ODE
The PR-680/680L can be instructed to automatically adjust the exposure time to the frequency of the
source. This can significantly improve the accuracy and precision of the measurement of repetitive,
intense sources. When measuring these types of sources, the instrument may only be exposed to a very
few “pulses” of light. Since the instrument has no way of knowing at what point in the pulse the
measurement started (e.g. leading edge or trailing edge) two successive measurements of the same
stimuli may yield unacceptably different results. By knowing the frequency of the source, the exposure
time can be adjusted to an even multiple of the pulse rate thereby insuring that entire pulses are
captured improving the accuracy and repeatability of the measurements. This is not an issue if the
repetitive source being measured is relatively low level yielding a long (> 1 second) exposure time.
There are three SYNC modes,
None, Automatic and Manual. If set to None, no modification of the
exposure time will occur. In Automatic mode, the instrument samples the rate of the source and in
Manual mode the user inputs the frequency of the device under test.