13
12
ESCAPE
button or
LED ON/OFF
Active
SETTING
MENU or
SELECT
button
Use Rotary Knob or Arrow Buttons to adjust
ESCAPE
button or
LED ON/OFF
Active
SETTING
MENU or
SELECT
button
Use Rotary Knob or Arrow Buttons to adjust
When the strobe is used on reciprocating or rotating targets there is a downside to the
wider
fl
ashes. All strobes work by giving short bursts of light (the pulse width) at a rapid
repetition rate (the
fl
ash rate). Strobes rely on the persistence of the human eye (the
ability to remember an image) and its response to bright light to give an apparent stop
motion image. Imagine a shaft rotating at 6000 RPM or one rotation every 1/100 of a
second (10 msec). If the strobe
fl
ashes once every 10 msec for a brief moment, the user
sees the
fl
ash at the same spot in the rotation of the shaft and the persistence of the eye
remembers this until the next
fl
ash making the shaft appear to be stopped. As the target
is rotating there is some movement evident during the strobe
fl
ash. The longer the
fl
ash
duration, the more obvious the rotation is and this increases the blur.
6.1 Calculating Blur
Blur can be calculated – if the shaft takes 10 msec to complete one revolution and the
strobe
fl
ash duration is 100
μ
sec (1/100 of a millisecond), the shaft will turn:
(
fl
ash duration/time per rotation) x 360°, which is (.0001/.01) x 360 = 3.6°
So you will see the shaft move 3.6°. As the
fl
ash pulse widens you will see greater
degrees of rotation which results in more blur and a brighter perceived illumination
(the LEDs are on longer so the average light the eyes see is greater). The trade-o
ff
is
blur versus brightness. One also has to take into account tangential velocity (rota-
tional speed) – the further away the rotating point is from the center axis the faster
the tangential velocity and the worse the blur appears to be – it is always the same
number of degrees of rotation but the physical length of the blur gets bigger as the
point moves faster. The strobe adjusts the width of the pulse automatically to keep the
degree of rotation visible constant.
There are multiple ways of adjusting the
fl
ash pulse width and hence the brightness
and consequently the blur. For setting clarity see section 5.2 WIDTH / CLARITY menu
option.
6.2 Degrees of Rotation
This method (mutually exclusive with Percent of Duty Cycle – see MISC menu), is to
adjust the
fl
ash pulse width for degree of rotation visible (blur). The user can set this
from 0.1 to 4.0 degrees (3.0° for illumiNova 50) out of 360. The higher the setting the
brighter the strobe appears to be but the more blurred the target is. The number of
degrees is a proportional amount and remains constant as the
fl
ash rate increases or
decreases. The strobe automatically calculates how wide the pulse width should be at
di
ff
erent
fl
ash rates to keep the blur constant – the faster the
fl
ash rate the narrower
the pulse width. The pulse width equals:
(setting in degrees/360) x (1/
fl
ash rate in Hz)
Thus the blur remains constant no matter what the
fl
ash rate. In the event that the set-
ting exceeds the maximum settings when changing
fl
ash rate, the strobe will limit the
value and the DEG icon will blink on the display.
6.3 Percent of Duty Cycle (Coming Soon)
The duty cycle between
fl
ashes is 100%. The user can adjust the duty cycle, which is
the ratio of on time to o
ff
time, in percent (%). In the event that the setting exceeds
the maximum settings when changing
fl
ash rate, the strobe will limit the value and the
% icon will blink on the display.
PPR. If for example the input is from a 600 pulse per revolution optical encoder and
the strobe is to
fl
ash once per revolution, set the prescale to 600.
When
PRESC
is displayed press the MENU button to select and the current prescale
value (default is 1) will be displayed. Press the UP
and DOWN
arrow buttons
or knob to increment or decrement the digit. The LEFT
or RIGHT
arrow buttons
will change the digit that blinks and allow the user to edit another digit. Press the
MENU button to accept the new value and exit from the Prescale menu.
5.6.6 Engineering Units -
UNITS
Engineering Units options are Revolutions Per Minute (RPM), Revolutions Per Sec-
ond (RPS), Flashes Per Minute (FPM), or Flashes Per Second (FPS).
When
UNITS
is displayed press the MENU button to select and the current selec-
tion will be displayed as indicated by the Active SETTING icon. Use the UP
and
DOWN
arrow buttons or knob to choose an option and then press the MENU
button to select that option. Press the ESCAPE button to exit to the MISC menu.
5.6.7 Input Pulse Active Edge -
INPUT
Input pulse active edge options are POS for positive leading edge, and NEG for
negative going edge. The input pulse active edge is important when using an
external source to trigger the
fl
ash. Choosing the wrong edge may cause the
strobe to
fl
ash erratically.
When
INPUT
is displayed press the MENU button to select and the current selec-
tion will be displayed as indicated by the Active SETTING icon. Use the UP
and
DOWN
arrow buttons or knob to choose an option and then press the MENU
button to select that option. Press the ESCAPE button to exit to the MISC menu.
5.6.8 Output Pulse Polarity -
OUTP
Output pulse polarity options are POS for positive leading edge, NEG for negative
going edge, and SER (factory use only). The output pulse polarity is important
when triggering an external device. Choosing the wrong edge may cause the
device to function erratically.
When
OUTP
is displayed press the MENU button to select and the current selection
will be indicated by the Active SETTING icon. Use the UP
and DOWN
arrow
buttons or knob to choose and option and then press the MENU button to select
that option. Press the ESCAPE button to exit to the MISC menu.
5.6.9
Backlight
-
BKLIT
This controls the display backlight ON or OFF condition.
When
BKLIT
is displayed press the MENU button to select. Use the UP
and
DOWN
arrow buttons or knob to choose On or OFF (backlight will turn on or
o
ff
) and then press the MENU button to select that option. Press the ESCAPE but-
ton to exit to the MISC menu.
6.0 STROBE CLARITY
The width of the
fl
ash will determine the clarity (blur) of the target. The narrower the
fl
ash width the more focused the target will be. The width of the
fl
ash will also a
ff
ect the
brightness of the target, the wider the
fl
ash, the brighter the target will be perceived to
be. This is not to be confused with the Brightness menu setting which adjusts intensity.
