(
fl
ash dura on/ me per rota on) x 360°,
which is (.0001/.01) x 360 = 3.6°. So you will
see the sha appear to move 3.6°.
As the
fl
ash pulse widens you will see greater
degrees of rota on which results in more blur
and a brighter perceived illumina on (the
LEDs are on longer so the average light the
eyes see is greater). The trade o
ff
is blur
versus brightness. The further away the
rota ng point is from the center axis the
faster the tangen al velocity and the worse
the blur appears to be.
When se ng the pulse dura on in degrees,
what you set is what you get. Refer to the
image on the right for the di
ff
erence between
a 1° and 5° (of rota on)
fl
ash dura on.
There are two methods of adjus ng the
fl
ash pulse width and hence
the brightness and consequently the blur. For se ng Brightness see
Brightness (BRITE) Menu.
6.2
Brightness in Degrees of Rota on
Brightness can be set from 0.2 to 14 degrees out of 360. The higher the
setting the brighter the strobe appears to be but the more blurred the
target is. Optimal setting to stop motion is 1.8 to 3.6°. The number of
degrees is a proportional amount and remains constant as the flash rate
increases or decreases. The strobe automatically calculates how wide
the pulse width should be at different flash rates to keep the blur
constant*—the faster the flash rate the narrower the pulse width. The
pulse width equals: (setting in degrees/360) x (1/flashrate in Hz).
25
6.3 Brightness in Pulse Dura on
Brightness can also be set to a fixed duration pulse in microseconds. The
flash rate remains constant irrespective of the flash rate, thus as the
flash rate increases, the image will get brighter and more blurred.
Note: There are two limits maintained by the strobe – the flash pulse
width can never be greater than 2.0 msec (milliseconds) nor can it
exceed 14° of rotation.
The strobe automatically adjusts the pulse width and rotation values as the
flash rate is increased or decreased to maintain the limits at all times. For
example—a flash rate of 600 flashes per minute (10 Hz), 14° of rotation
represents a flash pulse width of 3.8 msec. The strobe will limit this value to
2.0 msec or 7.3° of rotation (blur).
7.
STROBE
DELAY
The Nova-Pro UV has mul ple special e
ff
ects that can be used to inspect
moving machinery in di
ff
erent ways. The Delay e
ff
ects depend on
whether a Laser Module is installed and the Mode of Opera on. Delay,
or Phase Shi ing, allows the user to view di
ff
erent posi ons of the
rota ng machinery rela ve to a virtual or
fi
xed trigger point (via External
sensor or internal Laser).
7.1 Internal Phase Delay
In the internal STROBE Mode the Delay is rela ve and no external
trigger is used. This is referred to as JOG. Once the
fl
ash rate has
been adjusted to give a stopped mo on image, the JOG bu ons (
e
and
f
icons on the touchpad) may be used to increase or decrease
the phase of the image with respect to its original posi on by the
amount set in the JOG Menu.
26
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