Jadak Photo Research SpectraScan PR-7 Series, User Manual

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Chapter 5
– Setup Menu
46
The PR-7XX has two Adaptive sensitivity ranges
–
Standard and Extended. You can select which range the
Adaptive Sensitivity algorithm uses. For Standard sensitivity, the exposure time range is 7 ms to 120,000 (2
minutes) ms. For Extended sensitivity, the exposure time ranges from 7 ms to 300,000 (5 minutes) 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.
H
OW TO
S
ET 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, 4X Fast by approximately 8 times, 8X Fast by approximately 16 times and
16X Fast by approximately 32 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, 4X Fast, 8X Fast or
16X Fast.
H
OW TO
S
ET THE
SYNC M
ODE
The PR-7XX 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 (non-DC), 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 train 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 frequency 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, obviously 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.
To set the SYNC mode:
1. Make sure Adaptive is set to Enabled.
2.
Touch the ▼ or ▲ icon in the
SYNC field to toggle between None, Custom, Learn, and Automatic.
3. If Manual is selected, touch the field adjacent to Frequency to access the following data entry screen :