– 10 –
DIV (pulse divider)
This function is only active when an external trigger signal is
employed. With the pulse divideryou can set a value x, by which the
external trigger signal is then divided.
Example:
An external trigger (e.g. rotation sensor) scanning a gear
wheel issues a signal forevery tooth scanned. At a DIV value of 10,
only every tenth input pulse is transmitted to the connected
stroboscope as a trigger signal.
OPT
Trigger signal edge selection. 0 = positive edge, 1 = negative edge.
With this option, the polarityof the trigger signal can be defined.
7.0 SAFETY PRECAUTIONS
Stroboscopes give the illusion of stopped motion.
Do not touch the machine or object being observed.
The use of stroboscopes may induce an epileptic seizure
in those persons predisposed to this type of attack.
Do not use this product in an explosive environment.
Do not use this product in wet or condensating
environments.
Do not allow liquids or metallic objects to enter into the
ventilation holes.
Wear adequate eye protection when using this product.
Failure to do so could result in serious injury.
The DS-2000LED / DS-2000LED-OT are designed for
battery operation only.Do not operate the instrument
while it is recharging. Failure to follow these
instructions willdamage the unit and void its warranty.
DANGER HIGH VOLTAGE!
To reduce risk of an electronic shock, do not open the
stroboscope. There are no user-serviceable parts inside.
– 11 –
8.0 SLOWING DOWN MOTION
As discussed, the primary use of the strobe is to slow down or “freeze”
the apparent motion of moving objects. This allows you to analyze their
run-time performances safely and easily.
To make an object appear to move in slow motion, you need to strobe it
at a rate slightly above or slightly below its actual speed or any
harmonic of its speed as discussed below.
Helpful Hints:
The speed at which the object appears to move can be determined by
subtracting the flash rate from the object’s actual rate.
Example:
If an object is rotating at 1,000 RPM and you strobe it at a
rate of 1,005 flashes per minute (FPM), the object will appear
to be moving at a rate of 5 RPM.
Speed
= Actual Rate minus Flash Rate
= 1,000 –1,005 = 5
=
5 RPM
The direction (clockwise vs. counterclockwise or forward vs. backward)
at which the object appears to move is determined by the flash rate,
the object’s actual direction of movement and the orientation of the
stroboscopic beam to the object.
Example:
Assume you wish to visibly slow down the movement of a fan
which is rotating clockwise at 1,000 RPM.
Case 1:
If you stand in front of it and strobe it at a rate of 1,005
flashes per minute (FPM), the object will appear to be moving
at a rate of 5 RPM in a counterclockwise direction.
Case 2:
If you stand in front of it and strobe it at a rate of 995 FPM,
it will appear to move at a rate of 5 RPM in a clockwise
direction.
Case 3:
If you stand behind it and strobe it at a rate of 1,005 FPM,
it will appear to move in a clockwise direction at a rate of 5
RPM.
Case 4:
If you stand behind it and strobe it at a rate of 995 FPM, it
will appear to move in a counterclockwise direction at a rate
of 5 RPM
NOTE:
Typically, stroboscopes are brightest (and can illuminate an
object the best) when the flash rate is between 2,000 and 6,000
FPM. Often, you can still make an object appear to be frozen or
moving in slow motion within this range because of the effect
of harmonics. This principle is explained section 9.0.
CAUTION
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