MONARCH INSTRUMENT PLS User manual

Pocket LED Strobe
Portable LED Stroboscope
15 Columbia Drive • Amherst, NH 03031 USA
Phone: [phone] • Fax: [phone]
E-mail: [email protected]
Website: www.monarchinstrument.com
Instruction Manual

Safeguards and Precautions
1. Read and follow all instrucons in this manual carefully, and retain this manual
for future reference.
2. Do not use this instrument in any manner inconsistent with these operang
instructions or under any conditions that exceed the environmental
specificaons stated.
3. Certain strobe frequencies can trigger epilepc seizures in those prone to that
type of aack.
4. Users should not stare directly at the light source.
5. Prolonged exposure to the light can cause headaches in some people.
6. Objects viewed with this product may appear to be staonary when in fact they
are moving at high speeds. Always keep a safe distance from moving machinery
and do not touch the target.
7. There are no user serviceable parts in this instrument. Refer service to a
qualified technician.
8. Do not allow liquids or metallic objects to enter the stroboscope as this may
cause permanent damage and void the warranty.
9. Do not clean this instrument with alcohol or other cleaning solvents as these
may damage the LEDs.
10. The Pocket LED Strobe contains Lithium Ion baeries which must be disposed
of in accordance with Federal, State, & Local Regulaons. Do not incinerate.
Baeries should be shipped to a reclamaon facility for recovery of the metal
and plasc components as the proper method of waste management. Contact
distributor for appropriate product return procedures.
11. This instrument may not be safe for use in certain hazardous environments, and
serious personal injury or death could occur as a result of improper use. Please
refer to your facility’s safety program for proper precauons.

In order to comply with EU Directive 2012/19/EU on Waste Electrical and Electronic
Equipment (WEEE): This product may contain material which could be hazardous to
human health and the environment. DO NOT DISPOSE of this product as unsorted
municipal waste. This product needs to be RECYCLED in accordance with local
regulations, contact your local authorities for more information. This product may be
returnable to your distributor for recycling - contact the distributor for details.
Monarch Instrument’s Limited Warranty applies.
See www.monarchinstrument.com for details.
Warranty Registration and Extended Warranty coverage available online at
www.monarchinstrument.com.
TABLE OF CONTENTS:
1.0 INTRODUCTION .............................................................1
2.0 USER INTERFACE............................................................2
3.0 GETTING STARTED .........................................................3
3.1 Power ............................................................................ 3
3.2 Input/Output Connecons............................................ 3
4.0 MODES OF OPERATION..................................................4
4.1 Internal Strobe Mode.................................................... 5
4.1.1 Adjusng the Flash Rate - RPM.......................... 5
4.1.2 Doubling or Halving the Flash Rate.................... 5
4.2 External Mode............................................................... 6
4.3 Charnging Mode............................................................ 6
5.0 MENU OPTIONS.............................................................6
5.1 MODE ............................................................................ 7
5.2 BRITE (Brightness) ......................................................... 8
5.3 SAVE .............................................................................. 8
5.4 LOAD.............................................................................. 9
5.5 UNITS............................................................................. 9
5.6 BKLIT (Backlight)............................................................ 9

5.7 DECPT (Decimal Point)................................................. 10
5.8 INPUT (INput Pulse Polarity) ....................................... 10
6.0 STROBE BRIGHTNESS ...................................................11
6.1 Calculang Blur ........................................................... 11
6.2 Brightness in Degrees of Rotaon............................... 12
6.3 Brightness in Pulse Duraon ....................................... 12
7.0 USING THE STROBOSCOPE TO MEASURE RPM............13
8.0 BATTERIES....................................................................15
8.1 Low Baery Indicaon ................................................ 15
8.2 Charging the Baeries................................................. 15
8.3 Baery Disposal .......................................................... 16
9.0 SPECIFICATIONS ...........................................................17
10.0 SENSORS / ACCESSORIES and PARTS............................19
Monarch Instrument holds the following US trademarks and registrations, all
rights reserved: Track-It™, Nova-Pro®, Nova-Strobe™, Data-Chart™ ©2018

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MENUEXT
1/4-20
Bushing
Charger
Jack
Battery
Cover
Input
Jack
Output
Jack
1.0 INTRODUCTION
The Pocket LED Strobe (PLS) is a rugged, portable battery powered LED
(Light Emitting Diode) stroboscope used for inspection and to stop motion to
determine the speed of rotating objects. The unit is ergonomically designed
for comfortable hand held operation or it may be mounted on a tripod using
the integral ¼ -20 UNC bushing on the underside of the unit.
Figure 1 Pocket LED Strobe

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2.0 USER INTERFACE
The Pocket LED Strobe has a two-line backlit alpha-numeric liquid crystal
display (LCD) and a four-key keypad that enables the user to control the
operation of the unit. The user interface is described in Figure 2 and Table 2.
Figure 2 Pocket LED Strobe User Interface
Table 2 Pocket LED Strobe User Interface
1 5-digit display used to display flash rate and other numeric values
2 Baery icon - Acve when the baery is low
3 On Target Indicator - Acve when the input is locked on to a target
4 Star icon - Used to indicate current selecon in the menus
5 POWER / LEFT Arrow buon - Turns the unit on and off. Also used as LEFT
Arrow for adjustments
6 MENU buon - Allows access to the menus. Also used to confirm
selecons
7 UP/DOWN buon - Used to adjust flash rate and menu navigaon
8 RIGHT Arrow - Used to adjust flash rate and menu navigaon
9 5-digit alphanumeric display used to display units and other statuses
10 EXT icon - Acve when an external source is plugged into the unit
EXT
MENU

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3.0 GETTING STARTED
The Stroboscope may be hand held or mounted on a tripod or other user
supplied bracket using the ¼-20 UNC bushing on the underside of the unit.
3.1 Power
The LED Strobe is battery powered and has internal rechargeable
batteries. The unit should be charged before use (see Section 8.0).
The actual operating time of the stroboscope depends on the flash pulse
width. Narrower flash widths increase the operating time.
To turn on the stroboscope, depress and hold the POWER button
until the display shows the rev level - RVXxX then release the button.
The unit will start up with the same settings in which it was last left.
To turn the power off, hold the POWER button until the display
shows OFF then release it.
3.2 Input / Output Connectors
The strobe has input and output jacks on the right
side of the stroboscope. These can be used for
external triggering or synchronization (daisy-
chaining two or more strobes). These jacks accept
1/8” (3.5mm) phone plugs (input - stereo, output
- mono). The input and output signals are TTL
compatible. Connection details are shown in
Figures 3 and 4 on the next page.
Input
Jack
Output
Jack

4
Figure 3 Input Connector Detail (Stereo plug)
Figure 4 Output Connector Detail (Mono plug)
With no external input, the output jack provides a TTL compatible pulse
from the strobe’s internal oscillator. If an external input is applied, the
output pulse is in sync with the input pulse. This output pulse may be
used to trigger a second stroboscope synchronously to illuminate larger
areas. Many strobes can be “daisy chained”. The output jack of one
strobe is connected to the input jack of the next strobe causing all the
strobes to flash together and be controlled by the first strobe in the chain.
Note: Cables should not exceed 8 feet or 2.5 meters in length in
order to comply with the CE rating of this product.
4.0 MODES OF OPERATION
The stroboscope has two basic modes of operation – INTERNAL and
EXTERNAL. The unit does not operate when in the Charging Mode.
Signal Output
Common (GND) Signal Output
Common (GND)
Signal Input
+3.2V Out to
Sensor
Common (GND) Signal Input
+3.2V Out to
Sensor
Common (GND)

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4.1 Internal Mode
The strobe is in the Internal Mode when nothing is plugged into the input
jack. In the internal mode the strobe generates its own timing signals
and the user can adjust the flash rate as described below.
4.1.1 Adjusting the Flash Rate - RPM
The flash rate can be adjusted by pressing the large UP/DOWN
button. Pressing the UP end of the button ▲ will increase the flash
rate and pressing the DOWN end of the button ▼ will decrease the
flash rate. The flash rate can be adjusted in decades by pressing the
LEFT ◄ or RIGHT ► buttons which will change which digit is
adjusted. The active digit will blink. As the flash rate is increased
or decreased, the active digit will roll over to the next significant
digit. The LEFT and RIGHT digit selection will wrap around as
shown below.
4.1.2 Doubling or Halving the Flash Rate
The strobe flash rate can be instantly doubled (x2) or halved (÷2)
by pressing the MENU button. The lower display will show X2/2.
Pressing the UP/DOWN button will double ▲or halve the flash
rate. This is useful in determining actual rotational speed – refer to
the section on speed measurement – Section 7. Note that if doubling
or halving the flash rate will cause the strobe to exceed its capability,
the unit will be limited to the highest or lowest value it can generate
respectively. To exit this mode, press the LEFT ◄button.

KKKKKK
> > > > > > > >


KKKKKK
< < < < < < < <

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4.2 External Mode
In the External Input Mode the user can’t make any flash rate
adjustments. The flash rate is a function of the input signal. This mode
is used to synchronize the flash to an external event (for example, from
an optical sensor) to stop or freeze motion. The flash will be triggered on
the rising or falling edge (menu selectable) of the external input pulse.
The input jack enables an external signal to trigger the strobe. Inserting
a plug into the input jack will automatically put the strobe into the
External Mode. When the strobe is in the External Input Mode, EXT
will be displayed.
When an external input is applied to the unit and the strobe is put in the
Tachometer Mode, the unit will read the signal from the external input
(sensor) and display the reading on the LCD display without flashing
the lamp. When there is a valid external signal the on target indicator
will turn on. The strobe will not flash in the Tach (Tachometer) Mode.
To exit the External mode, remove the device from the input jack and
the strobe will be put back into the Internal Mode.
4.3 Charging Mode
The Charging Mode is when the strobe has the battery recharger plugged
into it. The strobe will not operate while charging. The status of the
charge is indicated by the LED on the charger. While charging the LED
on the charger is RED; when the charge is complete the LED will turn
GREEN. USE ONLY THE CHARGER SUPPLIED WITH THE
STROBE - Model LBC-U.
5.0 SETUP MENU OPTIONS
To enter the Setup Mode it is necessary to press the MENU button twice.
The first press will enter the x2 /2 mode as described in section 4.1.2; the

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second press will enter the Setup Mode. The top line of the display will show
SEtUP and the bottom line will show the setup options. Use the UP/DOWN
button ▲▼ to scroll through the setup options. Press the MENU button at
any time to select that setup option. Note that currently selected options are
indicated by the star icon ( ).
Setup options are in order as follows:
MODE > BRITE > SAVE > LOAD > UNITS > BKLIT > DECPT > INPUT
These options are described in the following sections. Note that the order
of the options within each setup option may change depending on current
operating settings.
5.1 MODE
Set the strobe into the flash (strobe) mode or the tachometer (no flash)
mode. When the display shows:
SETUP
MODE
Press the MENU button to enter. The mode can be set to Tach or Strobe.
Tach - No LED flash - use external input to show RPM
TACH
MODE
Press MENU to save and return to the main menu, or use UP/
DOWN button ▲▼ to change to:
Strobe - Internal generator - flash LEDs
STRBE
MODE
Press MENU to save and return to the main menu or press to return
to the main menu without saving. The unit will indicate DONE when the
value has been changed.

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5.2 BRITE (Brightness)
Adjust the flash pulse width and consequently the brightness. See Section
6.0. When the display shows:
SEtUP
BRITE
Press the MENU button to enter. Width can be set in degrees or
microseconds.
DEG - Set the flash width in degrees from 0.1° to 10.0°. Use the UP/
DOWN button ▲▼ to change the degrees in 0.1° steps. Note that
the decade being edited can be changed using the LEFT or
RIGHT ► buttons.
5.6
DEG
Press the MENU button to move to microseconds.
uSEC - Set the flash width in microseconds from 0.5 to 1300 µsec. The
display will default to a conversion of the degrees to microseconds
for the current flash rate.
1234
uSEC
To accept this press MENU again. To adjust the flash rate in
microseconds, use the ▲▼ button. Note that the decade being
edited can be changed using the LEFT ◄ or RIGHT ► buttons.
Press MENU to save and return to the main menu.
5.3 SAVE
Saves the current flash rate to a memory location. When the display
shows:
SEtUP
SAVE
Press MENU to select, use the UP/DOWN button ▲▼ to select a

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memory location, press MENU to select the location. The flash rate is
shown on the top row, memory location on the bottom row (see below).
3600
SM 3 (SM = Save Memory)
Press MENU to save and EXIT OUT OF MENU. The unit will indicate
DONE when the value has been changed.
5.4 LOAD
Loads the saved flash rate from a memory location. Press MENU to
select, use the UP/DOWN button ▲▼ to select the memory location,
press MENU to select. The flash rate is shown on the top row, memory
location on the bottom row (see below).
3600
RM 3 (RM = Recall Memory)
Press MENU to recall flash rate and EXIT OUT OF MENU.
5.5 UNITS
Selects the engineering units for the display. When the display shows:
SEtUP
UNITS
Press MENU to select, use the UP/DOWN button ▲▼ to select the
units. The units depend on the MODE of the unit. The options are RPM/
RPS (Revolutions per Minute/Second).
Unit
RPM
Press MENU to save and exit back to the main menu or press to
return to the main menu without saving. The unit will indicate DONE
when the value has been changed.
5.6 BKLIT (Backlight)
Turns the display backlight on or off. When the display shows:
SEtUP
BKLIT

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Press MENU to select, use the UP/DOWN button ▲▼ to select on
or off. As the status changes, the backlight will activate accordingly.
OFF
BKLIT
Press MENU to save and exit back to the main menu.
5.7 DECPT (Decimal Point)
Set the number of decimal places to display. When the display shows:
SEtUP
DECPT
Press MENU to select, use the UP/DOWN button ▲▼ to select none,
1 or 2.
nonE
DECPT
Press MENU to save and exit back to the main menu or press to
return to the main menu without saving. The unit will indicate DONE
when the value has been changed.
5.8 INPUT (Input Pulse Polarity)
Set the active edge of the input pulse. When the display shows:
SEtUP
INPUT
Press MENU to select, use the UP/DOWN button ▲▼ to select
NEGative or POSitive.
nEg
EDGE
Press MENU to save and exit back to the main menu or press to
return to the main menu without saving. The unit will indicate DONE
when the value has been changed.
At the MAIN MENU press the LEFT button to exit to the operational
condition.

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6.0 STROBE BRIGHTNESS
The strobe’s brightness depends on how wide the strobe’s flash pulse is; the
wider the pulse, the brighter the flash from the LEDs appears to be. There is
however, a downside to the wider pulses. All strobes work by giving short
bursts of light (the pulse width) at a rapid repetition rate (the flash rate).
Strobes rely on the persistence of the human eye (the ability to remember
and 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 flashes once every 10 msec for a brief
moment, the user sees the flash at the same spot in the rotation of the shaft
and the persistence of the eye remembers this until the next flash making
the shaft appeared to be stopped. As the target is rotating there is some
movement evident during the strobe flash. The longer the flash duration, the
more obvious the rotation is and this increases the blur.
6.1 Calculating Blur
Blur can be calculated– if the shaft is turning at 6000 RPM, it takes 10
msec to complete one revolution. If the strobe flash duration is 100
µsec (1/100 of a millisecond), the shaft will turn: (flash duration/time
per rotation) x 360°, which is (.0001/.01) x 360 = 3.6°. So you will see
the shaft appear to move 3.6°.
As the flash 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 off
is blur versus brightness. The further away the rotating point is from
the center axis the faster the tangential velocity and the worse the blur
appears to be.

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When setting the pulse duration in degrees,
what you set is what you get. Refer to
the image on the right for the difference
between a 1° and 5° (of rotation) flash
duration.
There are two methods of adjusting the
flash pulse width and hence the brightness
and consequently the blur.
6.2 Brightness in Degrees of
Rotation
The first method is to adjust the flash
pulse width for degree of rotation visible
(blur). The user can set this from 0.1 to 10
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 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/flash rate in Hz).
Thus the blur remains constant no matter what the flash rate*.
6.3 Brightness in Pulse Duration
The second method is to adjust the flash pulse width to a fixed number of
microseconds. Here the user sets the flash pulse width in microseconds
not degrees. As the flash rate increases, the pulse width stays the same*
and the image will get brighter and more blurred as the flash width

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remains constant*. The degree of rotation visible changes to keep the
pulse width of the flash constant*.
*Note: There are two limits maintained by the strobe – the pulse can
never be greater than 1300 µs nor can it exceed 10° of rotation. The
strobe automatically adjusts these values as the flash rate is increased
or decreased to maintain these limits at all times.
7.0USING THE STROBOSCOPE TO MEASURE
RPM
The primary use for a stroboscope is to stop motion for diagnostic inspection
purposes. However the stroboscope can be used to measure speed (in RPM
/ RPS). In order to do this several factors need to be considered. First, the
object being measured should be visible for all 360° of rotation (e.g. The
end of a shaft). Second, the object should have some unique part on it, like a
bolt, key way or imperfection to use as a reference point. If the object being
viewed is perfectly symmetrical, then the user needs to mark the object with
a piece of tape or paint in a single location to be used as a reference point.
Look only at the reference point.
If the speed of rotation is within the range of the stroboscope, start at a
higher flash rate and adjust the flash rate down. At some point you will stop
the motion with only a single reference point of the object in view. Note that
at a flash rate twice the actual speed of the image you will see two images
(reference points). As you approach the correct speed you may see three,
four or more images at harmonics of the actual speed. The first SINGLE
image you see is the true speed. To confirm the true speed, note the reading
and adjust the stroboscope to exactly half this reading, or just press the ÷2
button. You should again see a single image (which may be phase shifted
with respect to the first image seen).
For example, when viewing a shaft with a single key way you will see one
stationary image of the key way at the actual speed and at 1/2, 1/3, 1/4, etc.

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of the actual speed. You will see 2 images of the key way at 2 times the actual
speed, 3 key way at 3 times, etc. The FPM equals the shafts Revolutions Per
Minute (RPM) at the highest flash rate that gives only one stationary image
of the key way.
Example: Object rotating at 3000 RPM
If the speed is outside the full scale range of the stroboscope (300,000
FPM), it can be measured using the method of harmonics and multipoint
calculation. Start at the highest flash rate and adjust the flash rate down.
You will encounter multiple images so be aware of these. Note the flash rate
of the first SINGLE image you encounter, call this speed “A”. Continue
decreasing the flash rate until you encounter a second SINGLE image. Note
this speed as “B”. Continue decreasing the speed until you reach a third
SINGLE image at speed “C”.
For a two point calculation the actual speed is given by: RPM = AB/(A-B)
For a three point calculation: RPM = 2XY(X+Y)/(X-Y)2where
X = (A-B) and Y = (B-C)
If a Remote Optical Sensor or Magnetic Sensor is used to sense one pulse per
revolution (External mode), the readout will display directly in RPM (FPM)
without any adjustment required.
In instances when you can shut down the device and install a piece of reflective
tape, then an optical tachometer is easier to use for RPM measurement.
Stroboscopes must be used when you can’t shut down the device. The
human eye is not easily tricked into seeing a stopped image by a stroboscope
when the flash rate is slower than 300 FPM. Therefore, stroboscopes are just
about impossible to use below 300 FPM for inspection or to measure RPM.
Stopped Image 1/4 times 1/2 times 1 time 2 times 3 times 4 times
Flash Rate (FPM) 1250 2500 5000 10000 15000 20000

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8.0 BATTERIES
The Pocket LED Strobe is fitted with a rechargeable Lithium Ion battery
pack. These batteries are prone to self-discharge over time. For maximum
performance, charge the batteries prior to use and do not store in hot loca-
tions. The strobe uses an external charger. Allow 3-5 cycles of charging and
discharging for batteries to reach full capacity. When not in use, the batteries
should be charged at least every three months, otherwise the battery capacity
will be reduced or the batteries may become unusable.
The enclosure contains control electronics to properly protect and safely
charge the batteries. Never remove the batteries from the enclosure and
attempt to charge externally. Always use the charger supplied – LBC-U.
5.1 Low Battery Indication
When the batteries are charged, there will be no battery icon indication.
When the batteries are low, the Low Battery icon will appear in the
display. The strobe may still be used for a short time.
Low Battery Icon = Outline blinking (very little time left)
The strobe has a protection feature that prevents the strobe from operating if
the battery voltage is too low. This condition is indicated by no flash and
the display shows “LO BAT”. At this time the batteries must be recharged.
5.2 Charging the Batteries
The unit may be recharged at any time. You do not need to wait until
the low battery condition is indicated.
To charge the strobe with the recharger:
1. Turn the strobe off.
2. Plug the Li-Ion charger cable into the recharger socket on the
left of the keypad.
3. Plug the recharger into an AC mains wall outlet (115/230 Vac).

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CAUTION: Use of rechargers other than the one supplied
(Model LBC-U) will damage the stroboscope and
void the warranty. DO NOT LEAVE A CHARGER
THAT IS NOT PLUGGED INTO THE AC POWER
CONNECTED TO THE STROBE.
When charging, the strobe will indicate CHRGE in the bottom right of
the display when turned on and then it will shut off. The recharger will
fast charge the batteries for about 4-5 hours and then trickle charge the
batteries.
The charger has an LED to indicate charge: LED Red = batteries
charging. LED Green = batteries charged or charger not connected.
The battery pack may be replaced by removing the battery cover and
unplugging the battery pack. The new battery pack can be inserted and
plugged into the unit. Replace the battery cover.
5.3 Stroboscope Disposal
Prior to disposing of the battery-powered strobe, the user
must remove the Lithium Ion batteries. To do this, remove
the battery cover, unplug the battery pack and dispose
according to local laws governing battery disposal. The
rest of the parts may now be disposed of.