Laser Optronix EG-LRF 20000 Parts list manual

EG-LRF 20000
technical description
and instruction manual

2
1. INTRODUCTION
This manual provides basic information that is necessary for proper operation
and preventive maintenance of the EG-LRF 20000 compact laser rangefinder.
A full description of the device operation and details of extensive repair and
technical servicing procedures are not given in this manual.
2. DESCRIPTION
2.1. General
The EG-LRF 20000 laser rangefinder is a device intended for the use by an
individual. The rangefinder can measure ranges from 60 to 20,000 m with an
accuracy of 5 m. The maximum range depends on a target size and shape as
well as weather conditions, and can exceed 20,000 m in case of good target
visibility.
The solid-state laser used in this EG-LRF rangefinder is classified as 1 Class of
laser hazard and its emission is eye-safe for people being within the laser beam.
The EG-LRF 20000 delivery set includes (see Fig.1):
- rangefinder;
- accumulator battery (2 pieces);
- accessory set;
- charger for accumulator batteries;
- technical description and instruction manual;
- carrying case.
2.2. Rangefinder
The external view of the rangefinder is shown in Fig.2.

3
Fig.1. EG-LRF 20000 rangefinder set:
1. Carrying case. 2. Rangefinder. 3. Accumulator battery.
1
3
2

4
a)
b)
1 – trigger; 2– MODE operating mode switch; 3 – desiccator with silica gel; 4 -plug to output
information on range; 5 -boresight eyepiece; 6– digital display ocular; 7 - ON supply switch;
8– external power supply and remote trigger plug; 9– MIN RANGE minimum range (gate)
handle ; 10 - battery compartment lid; 11 – receiving and sighting channel objective;
12– transmitting channel objective.
1
2
3
4
5
6
7
8
9
10
11
12

5
Fig. 2 - External view of rangefinder
_)viewed from the eyepiece panel; b) viewed from the front panel.
The rangefinder has the following controls: the ON power supply switch; the
MODE operating mode switch; the MIN RANGE handle for continuous
setting a minimum range (gate) on the eyepiece panel of the rangefinder as well
as the trigger on the topside of the rangefinder housing.
2.3. Battery
The rangefinder uses a NiCd rechargeable battery. The battery has a rated
voltage of 12 V and a capacity of 0.55 A⋅h that is sufficient for more than 300
rangings at +20°C.
2.4. Accessory set
The accessory set includes the following items:
1) Supply cable and cable to output information on range;
2) Cloth to wipe optical surfaces;
3) Silica gel to replace the wet one in the desiccator.
2.5. Charger for accumulator batteries
The AD-150-VD portable charger is designed to charge Ni:Cd battery of 12 V
voltage and capacity from 0.5 to 1.0 A.h. The charger is a stabilized DC
source.
Technical characteristics of the AD-150-VD:
Mains voltage
200...240 V
Charge current
60 mA±5%
Ambient temperature when operating
+5...+25°C
Power supply
no more than 1 W
2.6. Carrying case
The case is used for transportation and storage of the rangefinder. It protects the
latter from various mechanical damages during transportation and storage. The
whole of the rangefinder set is placed in the case.
It is possible to deliver the rangefinder in a metal case.

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3. DESIGN AND OPERATION
3.1. Principle of operation
The rangefinder operates on the same principle as the optical locator. A range is
determined by the time of passing of a short invisible laser pulse to a target
and back.
A short infrared light pulse of high intensity generated by the laser propagates
towards a target within a narrow cone. At the same time a small portion of the
pulse hits the photosensitive area of the photoreceiver and is transformed into
an electric pulse (start signal). The light pulse reflected from the target comes
to the receiving objective of the rangefinder and is transformed into an electric
pulse (stop signal). The time interval meter measures the time between these
two pulses and transforms it into the information on range.
3.2 Design and operation
The rangefinder block diagram is given in Fig.3.
The rangefinder consists of the following main parts: the transmitting (11, 12,
13, 14, 15) and receiving (9, 8, 7, 4) channels, the boresight (5, 6, 7, 8, 9),
the display and control unit (3).
The rangefinder optical configuration (Fig.4) provides formation of a laser
pulse and sighting it on the target, transmitting the start pulse, receiving a
light pulse reflected from the target and focusing it on the photoreceiver
photosensitive area, observing the readings on the digital display.
The transmitting channel (7) optics forms a laser pulse while reducing its
divergence. To ensure the parallelism of the receiving and transmitting
channels, there are two protective glass wedges (8) at the exit of the telescope
of the transmitting channel.

7

8

9
In the transmitting channel a laser pulse reflected from the target goes through
the protective glass (5), the receiving/sighting channel objective (4), the prism
unit (3) and is focused by the objective in the plane of the photosensitive area
of the photoreceiver (2).
The prism unit by its beam-splitting coating applied to the facet of one of the
prisms divides a laser pulse going through the objective into two portions. A
laser pulse at 1.054 µm passes to the photoreceiver, and a visible laser pulse is
reflected and focused in the plane of the eyepiece (1) reticule.
The boresight includes the objective (4) and the erecting prism unit (3)
integrated with the receiving channel, and the sight eyepiece (1).
The digital display unit consists of two mirrors (12) transmitting the image of
the digital display (11) to the eyepiece, and the display ocular (10).
The rangefinder operates in two modes: ranging mode (the MODE switch is in
the For L position) and control mode (the MODE switch is in the C
position)
When operating in the F mode, range measurement to the first target within
the rangefinder transmitter beam is carried out.
When operating in the L mode, range measurement to the last target within the
rangefinder transmitter beam is carried out.
When operating in the C mode, the value of minimum range is shown on the
digital display. By the MIN RANGE handle a necessary value of minimum
range is set within 40...4500 m.
3.2.1. Rangefinder operation in ranging mode (mode switch in F or L
position)
When the ON switch is switched on, the storage capacitor is getting charged
during ∼10 s. When it is charged, the ready indicator lights (Fig.4), and then
the storage capacitor is continuously recharged. To measure a range to a target,
the rangefinder cross-hairs at the center of the field of view of the sight
eyepiece is set on the target. When the trigger button is pressed, the storage
capacitor is discharged through the flash lamp of the laser, and a laser pulse is
generated. The major portion of a laser pulse is sent from the output of the
transmitting channel of the rangefinder to a target. At the same time a small
portion of the laser pulse hits the photosensitive area of the photoreceiver and
is transformed into an electric start pulse. The light pulse reflected from the
target is focused on the photosensitive area of the photoreceiver and is
transformed into an electric stop pulse. The time interval meter in the display
and control unit is started by the electric start pulse from the photoreceiver

10
and continues operating until the stop pulse from the photoreceiver stops the
count of pulses from the timing oscillator of the time interval meter. The time
interval between the start and stop pulses is transformed into the information
corresponding to a range to a target in metres that is displayed.
Besides the measured range, additional information is shown on the digital
display by the LEDs (Fig.5).
3.2.2. Rangefinder control in the CONTROL mode (the switch in the
position C)
After setting the supply switch to the position ON the value of minimum range
is output to the digital display. The value of minimum range depends on the
MIN RANGE position of the potentiometer handle and can be changed from
40 m for the extreme counter-clockwise position of the handle to 4500 m for
the extreme clockwise position of the handle. The accuracy of minimum range
setting is ±20 m.
When pressing the START button in the CONTROL mode, the control range
is measured to check the serviceability of the rangefinder timer. In this case
there is no laser pulse. The START and STOP electrical pulses are formed not
by the photoreceiver, but by the central processor of the rangefinder. If a value
of minimum range is less than 280 m, the digital display outputs a control
range of 304±5 m. If a value of minimum range is more than 320 m, but less
than 3500 m, the control range is to be 3750±10 m. For minimum ranges
more than 4000 m the control range is 18,432±10 m.
A deviation of displayed values of control ranges more than ±10 m from the
said nominal values is indicative of failure of the rangefinder.

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1
1
9
2
0
Ready indicator Run-down battery indicator
(green LED) (red LED)
a) Digital display readings in range measurement to one target
0
3
5
0
0
C-indicator
b) Digital display readings when the rangefinder detects a signal
reflected from a target gated out by the minimum range setting
0
3
5
0
0
M-indicator
c) Digital display readings when the rangefinder detects a signal
reflected from an object behind the measured target
d) Digital display readings when there is no start signal at the
photoreceiver input
0
0
0
0
0
e) Digital display readings when there is no signal reflected from
the target
Fig.5. Display of ranging results and rangefinder
serviceability
4. TECHNICAL DATA

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4.1. Transmitter
Wavelength, µm..............................
1.54
Pulse energy, mJ, ..................
5-8
Pulse width, FWHM, ns..................
∼30
Pump energy, J, no more..................
12
Pulse repetition rate, Hz...................
0.15
Beam divergence (80 % energy),mrad..
1
4.2. Receiver
Field of view of receiving channel,
mrad..............................................
1
Type of photodiode..........................
Avalanche Ge or PIN
photodiode
Entrance pupil diameter, mm.............
43
Range accuracy, m...........................
±5
Measurement range, m......................
60...20,000
Type of digital display......................
LED indicators observed
through eyepiece
Multiple target................................
1 target displayed, indica-tion
of more than 1 target
registered
Operating mode...............................
first/last target
Minimum range setting, m................
40...4500
Minimum range setting accuracy, m...
±20
4.3. Sight
Magnification.................................
7.5x
Field of view..................................
5.5°
Objective diameter, mm....................
43
Range of eyepiece dioptric setting.......
±4
4.4. Power supply
Built-in battery...............................
NiCd 12 V/0.55 A⋅h re-
chargeable battery
Rangefinder weight without battery, kg, no
more....................................
1.9
Range information output
RS232 interface
5. DIRECTIONS FOR USE
5.1. Safety measures

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Since the laser head power supply produces high voltage that is a threat to
human life, it is categorically prohibited to disassemble the housing of the
rangefinder when there is an accumulator battery.
5.2. Measurement procedure
1) make sure that the MIN RANGE handle is set to the extreme left position
or to a required minimum range value (see 5.3);
2) set the MODE switch to the F position (range measurement to the first
target);
3) set the supply switch to the ON position. The rangefinder power supply is
on;
4) rotate the eyepieces to obtain a sharp image of the eyepiece reticule and of
the digital display;
5) look into the right eyepiece and set the cross-hairs exactly on a target. When
the green ready indicator in the digital display ocular lights, smoothly press
the trigger button. Do not release the trigger button and take the readings from
the display. The range in meters is displayed when holding the trigger button
pressed;
ATTENTION! If the trigger button is pressed before the green ready
indicator lights, measurement will be made with a delay until the green
indicator lights.
6) if the M-indicator (multiple target) lights, carefully examine the target area
through the sight eyepiece to identify other targets (see Fig.6). For positive
identification of all targets the arrangement for minimum range setting can be
additionally used as explained in 5.3;
7) if the C-indicator lights, this means that one or more targets (without
indication of their number) are gated out by the minimum range setting.
Examine the target area through the sight eyepiece to identify the targets. If it
is necessary to measure a range to a target that is less than the minimum
range, reduce the minimum range setting and repeat the ranging procedure.
5.3. Use of arrangement for minimum range setting
To obtain reliable results, it is of first importance that an operator completely
understands the designation of the arrangement for minimum range setting.
Laser emission is reflected from various targets, and the receiver in the
rangefinder is not able to distinguish them from each other, so the shortest
range will be displayed, whether it be an obstacle or a target.

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The arrangement for minimum range setting is designed to facilitate
identification of individual signals reflected from targets and other objects in
the path of the laser beam.
By using this arrangement an operator is able to not receive (i.e. reject) signals
reflected from objects within a given minimum range (gated range). A value of
gated range can be set within 40...4500 m. For this purpose:
- set the MODE switch to the Cposition;
- switch on the ON switch;
- observe the value of minimum range in the left eyepiece;
- continuously rotating the MIN RANGE handle set a required value of
minimum range;
- set the MODE switch to the Fposition and measure the range to a target as
explained in 5.2.
Due to the fact that a portion of the transmitter beam is intercepted by objects
in front of a target, a signal from the target can be lower than the level of
operation of the rangefinder receiver, so, when measuring range, sight the
rangefinder on a target so that as few objects in front of the target as possible
are within the transmitter beam.
If the C-indicator lights, this means that one or more targets (without
indication of their number) are gated out by the minimum range setting.

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Controls position
MODE
switch
MIN RANGE
handle
Digital
display
readings
Notes
F
≤60
2200•
Target 2200 m. There is a
target behind the displayed
one (3500 m)
F
2250
•3500•
Target 3500 m. There is a
target behind the displayed
one (4200 m) and a target
within the gate (2200 m)
F
3550
•4200
Target 4200 m. There is a
target within the gate (3500
m)
L
≤60
4200•
Target 4200 m. There is a
missed target (3500 m)
L
2250
•4200•
Target 4200 m. There is a
missed target (3500 m) and a
target within the gate (2200
m)
Fig.6. Example of ranging with multiple targets

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5.4. Measurement of range to the last target
If a target to be measured is overlapped by close targets, the signals from which
come to the rangefinder, and there is no object within the transmitter beam
behind the target (i.e. the reflected signal from this object does not come to the
rangefinder), then a range to such a target is the easiest to be measured in the
last target measurement mode (the L mode).
Set the operating mode switch to the Lposition and make ranging according to
5.2.
5.5. Switching-off
The handle of the power supply switch should not be left in the ON position
for a long time since in this case the battery is quickly discharged. That's why
the rangefinder supply should be switched off on completion of rangings.
6. MAINTENANCE
6.1. General
It is prohibited to disassemble the rangefinder.
6.2. Operator's maintenance duties (preventive maintenance)
The necessary maintenance of the rangefinder includes execution of the
following operations:
1) in case of detection of damages, faults or performance degradation, inform
the manufacturer;
2) in case of contamination, wipe the optical surfaces, the housing, the control
handles of the rangefinder with the cloth from the Accessory set;
3) if the silica gel colour changes from blue to pink (in this case the silica gel
is saturated with moisture), replace the silica gel in the desiccator after prior
heating the replacement silica gel from the Accessory set until it becomes blue;
4) carry out charging the accumulator battery (when the battery discharge
indicator lights (see Fig. 5).
Carry out charging when the ON supply tumbler is switched off in the
following manner:
- set the charged accumulator battery into the rangefinder;
- insert the charger into the socket;
- connect the charger to the rangefinder through the plug to connect the cable
of external supply =12 (see Fig. 2). In this case the (Charge) indicator on the

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charger lights;
- charge time of the discharged battery is 14...14.5 h;
- disconnect the charger from the rangefinder.
5) after long-duration interval in operation with the rangefinder (more than one
month) it is necessary to carry out training of the energy storage capacitor of
the head supply unit.
Carry out training in the following manner:
a) shift the supply tumbler of the rangefinder to the ON position;
b) after 10...15 s press and release the start button;
c) repeat the operations according to the clause b) until the green readiness
indicator on the digital indicator display lights (see Fig.5), after that the
rangefinder is ready to measure.

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Appendix 1
DESIGNATION OF PINS OF RANGEFINDER EXTERNAL PLUGS
1. The plug to connect the external power supply and the remote trigger
button
- an external supply voltage of 12±2 V is applied to the pins 1,4 of the plug;
- the remote closure trigger button is connected to the pins 2,3 of the plug;
- a consumed current (average) is no more than 0.6 A.
Numbering of the pins of the plug
to connect the external
power supply and the remote
trigger button
The plug to connect the external power
supply and the remote
trigger button
(viewed from the side of the pins)
Circuit
Pin
+ 12 V
1
TRIGGER
2
TRIGGER
3
0
4
2. The plug to output information on measured range
The information on measured range is transmitted from the rangefinder to the
computer by direct connection to the COM1 (3F8h) 9-pin port.
To operate the computer, it is necessary connect the computer with the
rangefinder by the cable, to start the LRF.EXE control program on the disk,
and switch on the rangefinder.
LRF.EXE is the EG-LRF rangefinder control program to provide
communication of the rangefinder with the IBM PC having the WINDOWS
XP operational system. For normal functioning of the program a free disk
space of about 700 Kbytes for the control module and a space that is unknown
beforehand for storage of the LRF.LOG output files are necessary.
In the LRF.LOG files the measurement data of the whole of the program
session is recorded.
See the description of operation of the LRF.EXE program in the file Help.txt.
Numbering of the pins of the plug
to output information on range
The plug to output information on range
(viewed from the side of the pins)

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Circuit
Pin
RxD
2
TxD
8
SG
10
ACCEPTANCE CERTIFICATE
Product: Hand-held laser eye-safe rangefinder
Model: EG-LRF
Serial number______________
Name of parameter
Permissible
values
Actual values
Maximum range, m, no less
10,000
Minimum range, m, no more
60
Minimum range setting, m
40...4500
Time of rangefinder readiness for
measurement, s, no more
6
The product conforms with the technical requirements and is fit for operation.
Supplier
Laseroptronix
Enhagsslingan 23
187 409 Täby
Sweden