SHIMPO DT-315A - Manual (Page 2)

Operation Display P anel
True RPM Measurement
Shimpo stroboscopes are DUAL function instruments that give
the operator the illusion of “stopped motion” where in actuality
the equipment under observation is in a moving state. By
adjusting the flash rate, equipment in motion appears to be
standing still. With a slight adjustment, movement can be viewed
in apparent slow motion, which enables the operator or observer
to study the process in action. All Shimpo stroboscopes can
measure rotational (RPM) or reciprocating (strokes per minute)
speeds with the same high precision as with an electronic digital
tachometer.
To measure true revolutions per minute (RPM):
1. “Mark” the object to be measured by either visually noting
an inherent distinguishing characteristic (such as a label,
scratch, etc.) or physically marking the object with a small
piece of tape, pencil mark, etc.
2. Firmly plug in power cord.
3. Turn power switch on.
4. Turn setter from highest FPM downward.
5. The true RPM can be noted once the action appears frozen
and the first single image of the “mark” appears (see chart
below and accompanying diagram for further explanation).
6. To verify RPM reading, press “÷2”; a single image should
appear again.
1. LED display: Displays function and value
2. EXT: External mode indicator
3. INT: Internal mode indicator
4. B-CH: Battery charge indicator (DT-315A only)
5. FPM: Flash per minute indicator
6. deg: Phase shift degree indicator
7. mSec: Millisecond delay time indicator
8. Signal switch:Switches the unit from the external mode
to the internal mode (and vice-versa)
9. Display mode switch: When unit is set to the external
mode, the strobe will switch to RPM (FPM)/deg/msec
each time “MODE” is depressed
RPM (FPM) Displays flashes per minute
External input 0-35,000 RPM (FPM)
deg Displays flash delay in degrees
msec Displays flash delay in msec
10. Setter: Changes the flashing rate
11. (x2) Switch: In the internal mode, pressing “x2”
doubles the flashing rate
12. (+) Switch: In the internal mode,when object appears
to be standing still, pressing “+” will give the illusion
that the object is moving towards the rotating direction
at a speed of 1 rotation in 6 seconds
13. (÷2) Switch: In the internal mode, pressing “÷2” divides
the flashing rate by two
14. (-) Switch: In the internal mode, when object appears
to be standing still, pressing “-“ will give the illusion
that the object is moving in reverse at a speed of 1 rotation
in 6 seconds
15. Input and output connector:
PIN #1: +12V
PIN #2: Synch output signal
PIN #3: Input signal
PIN #4: 0V
16. Power cord (DT-311A) / AC adapter (DT-315A)
17. Power switch
Internal Triggering Mode
To operate the stroboscope in internal triggering mode:
1. Firmly plug in power cord.
2. Turn power switch on.
3. If internal indicator is not on, press “SIG”; the INT light
will then turn on.
4. Aim light beam at object under observation. The optimal
distance between the strobe and moving object is
approximately 2 feet.
5. Measure RPM by turning the setter to adjust the flashing
rate to the rotational speed of the object.
NOTE: To achieve a particular rate quickly, use the “x2” or
“÷2” switches and then the setter for fine tuning.
NOTE: Once the internal timer has expired, the strobe will stop
flashing and the display will flash rapidly. To restart the strobe,
turn power switch off, then on, and the cycle will repeat.
Shaft Rotation Flashes Flashes/ Stopped
(RPM) (RPM) RPM Shaft Images
6,000 4 times 4
4,500 3 times 3
3,000 2 times 2
1,500 1 time 1
750 1/2 time 1
500 1/3 time 1
At 1,500 RPM
1
2
4
3