e-survey ESL2 User manual

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Automatic Level
ESL2
INSTRUCTION MANUAL

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Contents
1. Equipment....................................................................................................5
2. Applications .................................................................................................5
3. Technical Data.............................................................................................. 6
4. Description...................................................................................................7
4.1 Instrument.......................................................................................... 8
4.2 Leveling Staffs.................................................................................... 9
4.3 Tripod...............................................................................................10
5. Instructions for Use ...................................................................................10
5.1 Unpacking and Setting Up................................................................10
5.2 Leveling Up.......................................................................................10
5.3 Focusing and Sighting ......................................................................11
5.4 Compensator Checking ....................................................................11
6. Measuring ..................................................................................................12
6.1 Normal Height Measurement ...........................................................13

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6.2 Distance Measurement from Stadia Readings (fig.2) ......................15
6.3 Precise Height Measurement with ESM1 (fig.3)..................................16
7. Testing and Adjusting.................................................................................19
7.1 Tripod...............................................................................................19
7.2 Circular Level(fig.5) ..........................................................................19
7.3 Horizontality of the Line of Sight ....................................................21
8. Care and Transport ....................................................................................24
8.1 Transport .........................................................................................24
8.2 Storage ............................................................................................25
8.3 Cleaning and Drying .........................................................................26

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1. Equipment
1.1 Standard Equipment
1x Set ELS2 Universal Automatic Level, with 360°/400g circle
1x Adjusting pin each container
1.2 Optional Accessories
ESM1 parallel plate Micrometer can be used with WILD NA2/NAK2 and
ESL2 Measuring range:10mm
Parallel Plate Micrometer ESM1
With glass reading scale Range Interval Estimation
10mm 0.1mm 0.01mm
2. Applications
Model ESL2 Automatic Level is adoptable for the second and third class
leveling, It is also used for general construction engineering and installation of
large size machines. The advantage of the automatic is that as soon as the
circular bubble is centered, the line of sight is horizontal for all pointings of
the telescope. Elimination of the traditional tubular level speeds up work and
improves accuracy.

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3. Technical Data
ESL2 ESL2+ESM1
Standard deviation of 1KM
double run ±1.0mm ±0.5mm
Telescope
Image Erect
Magnification 32x
Clear objective aperture 45mm
Shortest focusing distance 1.6m
Multiplication factor 100
Additive constant 0
Compensator
Working range ±14′
Setting accuracy ≤0.3″
Circular level sensitivity 8′/ 2mm
Horizontal circle 360°(400g)
Minimum reading 1°(1g)
Weight 2.5 kg

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4. Description
Fig.1 Automatic Level
1. Base plate 6. Telescope eyepiece
2. Footscrew 7. Press button
3. Horizontal drive, endless 8. Circular level
4. Telescope objective housing 9. Prism for viewing circular level
5.Optical sight 10. Focussing knob with cores/fine motion
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8
4
3
2
1
6
7
5
ESL2

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4.1 Instrument
The base plate (1) has a standard thread enabling the ESL2 tobeused on
any of our tripods which are sufficiently stable (and on any other tripod
having a 5/8″thread fixing screw). The rotatable upper partof the
instrument consists chiefly of the telescope with an optical mechanical
compensator. The compensating element is essentially a pendulum,
supported by four suspension tapes and carrying a prism. The rapes are ofa
special alloy to guarantee correct compensator functioning even at extreme
temperatures (-30℃to +50℃). Provided the circular bubble(8) (sensitivity 8′
per 2mm) has been set in its setting circle by turning thethree
footscrews(2). The line of sight will be automatically horizontal as the
pendulum will bewell within its working range of ±14′. The movement of
the pendulum is efficiently air damped.
The ESL2 is equipped with a press button(7) to check the functioning of the
compensator. When the button is pressed, before reading the staff, the
pendulum is given a slight tap and, as a result of the pendulum’s swing, the
staff image swings smoothly awayand then floats gently back to its original
position with respect to the horizontal cross hair. The observer is then
certain that the compensator is working and that the line of sight is

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horizontal. The press button also verifies the leveling upofthe
ESL2’ because the staff image will not show the correct movement on
pressing the button if the circular bubble is long away from its central
position, but the movement will be quicker and shorter due to the
pendulum reading its stop.
The eyepiece(6) with dioptric scale is turned to focus the reticle cross hairs.
After turning the bayonet locking ring anticlockwise, the eyepiece can be
removed and replaced by an optional eyepiece.
The reticle haswedged-shaped hairs for precise leveling with the parallel
plate micrometer, and a single horizontal hair for normal leveling staffs. It
also has 1:100 stadia hairs(6.2).
The focusing knob(10)is turned to obtain a sharp image of the staff.It has
a coarse and fine motion. Rotation ofthe instrument is friction-braked.
Fine-pointing is by means ofthe endless horizontal drive screw(3). The
drive has knobs ateach side for use with either hand.
4.2 Leveling Staffs
As the telescope of the ESL2 gives an erect image, leveling staffs with erect
numbers should be used. It is emphasized that the accuracy of leveling
depends just as much on the staffs as on the level.

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High quality staffs must be used.
4.3 Tripod
For normal leveling the model L tripod with telescopic legs is usually
preferred. For precise leveling and severe conditions e.g. strong wind the
model M tripod is recommended. As the fixing screw on all of our tripods
have the same thread however, any our tripods can be used. Each tripod
has a plastic cover for the tripod head.
5. Instructions for Use
5.1 Unpacking and Setting Up
When setting up the tripod. The legs must be trodden firmly into the ground.
The tripod head should be as horizontal as possible and height should be
such that the telescope eyepiece will be comfortably at the observer’s eye
level. With a telescopic leg tripod check that the clamps are tight. The
instrument is set on the tripod head.
5.2 Leveling Up
To level up the instrument turn the footscrews (2) until the circular level (8)
lies in the centre of its setting circle. The line of sight is then automatically

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set by the compensator to horizontal. For adjustment of the circular level,
please refer 7.2.
5.3 Focusing and Sighting
The telescope is pointed towards a uniformly light surface. Or a sheet of
white paper and the telescope eyepiece (6) is turned until the reticle
cross-hairs appear sharp and absolutely black. The eyepiece diopters scale
reading now indicates the correct setting for the observer’s eye. By looking
alone the optical (or open) sight (5) and turning the instrument by hand the
telescope is pointed roughly at the Leveling staff. Turn the focusing knobs
(10), which have coarse and fine motion. Until the staff image appears
sharp and free from parallax with respect to the cross hairs, i.e. there
should be no apparent movement between the horizontal hair and a staff
graduation when the observe moves his eye slightly up and down. To bring
the vertical cross-hairs exactly on to the centre of the staff turn the
horizontal drive (3).
5.4 Compensator Checking
Before reading the staff, when the button (7) is pressed, the staff image
swings smoothly away and then floats gently back to its original position

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with respect to the horizontal cross hair. Then the compensator is working
and the line of sight is horizontal. The press button also verifies the
leveling up of the ESL2, because the staff image will not show the
correct movement on pressing the button if the circular level is a long away
from its central position, but the movement will be quicker and shorter
due to the pendulum reaching its stop line. To level up the instrument
until the circular level lies in the centre of its setting circle.
6. Measuring
Before starting field work or after longer periods of storage/transport of
your equipment check the field adjustment parameters specified in this User
Manual.
Reduce possible vibrations by holding the tripod legs.
If the optical parts of your instrument are dirty of fogged, your
measurements can be affected. Keep clean all optical parts of your
instrument and follow the cleaning instructions specified in the User Manual.
Before starting work, let the instrument adjust to the ambient

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temperature.
6.1 Normal Height Measurement
Procedure:
1. After pointing at the staff, check the circular bubble is centered, then
press the push button to verify that the compensator is functioning and
finally read the position of the horizontal cross hair on the staff.
2. Because of the erect image telescope the staff numbers will increase
from the bottom to the top in the field of view.
3. Take the nearest whole centimeter value from the graduation below the
horizontal cross hair (114cm) and estimate the millimeters within the
centimeter interval cut by the cross hair (3mm). The reading in fig.3 is
therefore 1.143m. For line leveling of high accuracy, and as a check against
gross error, the staff readings of the cross hair and both stadia hairs should
be taken (the 3 wire method). The mean of the two stadia readings serves
as a check on the middle cross hair reading.

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Example:
Horizontal cross hair 1.143m
Upper stadia A1 1.216m
Lower stadia A2 1.068m
1/2(A1+A2) 1.142m
Should the telescope image tremble due to
ground vibrations or a strong wind, the
observer can reduce the effects by holding
the tripod legs at about their mid-point.
Fig.2

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6.2 Distance Measurement from Stadia Readings (fig.2)
Toobtain the distance, the readings ofthe upper (A1) and lower (A2) stadia
hairs are used. The difference between the two readings multiplied by
100 gives the horizontal distance from instrument to the staff (see fig.3)
ESL2 field of view with leveling staff
Height reading from horizontal hair 1.143m
Example: Upper stadia A1 1.216m
Lower stadia A2 1.068m
A1-A2 0.148m
× 100
Ho
rizontal Distance 14.8m
To simplify the distance reading, the footscrews closest to the line of sight
can be turned until the lower stadia hair is on a full decimeter value. Only
the upper stadia hair has now to be read and the subtraction is easier.

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6.3 Precise Height Measurement with ESM1 (fig.3)
For leveling work of very high accuracy the ESL2 is used with the parallel
plate micrometer ESM1. The micrometer is slipped onto the
telescope objective and locked in position by turning the locking knob.
Reading magnifier Micrometer knob
ESL2 leveling instrument
ESM1 parallel plate
micrometer Locking knob
Fig.3

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In sloping terrain, the lower part of the staff should not be used, as refraction
close to the ground can cause errors.
In sunny weather an umbrella should be used to shelter the instrument to
ensure that the level is protected from the glare of the sun.
Procedure:
1. Sequence of measurements is the same as with normal height leveling
measurement.
2. When reading the staff, turn the micrometer knob until a graduation line is
centered between the wedge-shaped hairs of the reticule.
3. Centimeters are read from the staff and millimeters from the micrometer
scale.
4. Invar staffs have two sets of graduations. These are read alternatively
between foresight and back sight. This provides two independent results and

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serves as a check.
Example above：
Staffreading 77cm
Micrometer reading 0.556cm
Height 77.556cm
Fig.4

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7. Testing and Adjusting
7.1 Tripod
There should be no play between the various components of the tripod. The
hexagonal key should be used to tight up the tripod screws when necessary.
The hinges between the tripod head and the legs can be adjusted; they
should be sufficiently stiff so that when the tripod is lifted by its head, the
legs just remain spread-out.
7.2 Circular Level(fig.5)
The tripod, with instrument attached, is set up on firm ground. Using the three
footscrews, the circular bubble is centered exactly in the middle of the setting
circle. The instrument is now rotated through 180°. If the bubble is displaced,
it no longer lies within the setting circle it should be adjusted. When doing this
the bubble’s cover must not be touched with the finger. Half of bubble
displacement is taken out with the footscrews and the other half with two
adjustment screws.

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Fig.5 Adjusting the circular bubble.
As an adjustment screw is tightened the
bubble runs towards it and, as it is loosened,
the bubble runs away from it. The first
adjustment screw to be turned, therefore, is
the one that is the nearest to being in line with the middle of the bubble and
the centre of the setting circle. It is turned only until the bubble reaches the
centre of the circle or until it can be set in the centre by means of the other
screw. It is necessary to complete the adjustment that the screws must not be
tuned more than. The circular bubble is in correct adjustment when it stays in
the centre of the circle in whatever direction the telescope is pointing. Keep
the circular level in adjustment, thereby ensuring that the compensator will
always be well within its working range.

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7.3 Horizontality of the Line of Sight
7.3.1 Testing (Fig.6)
In flat terrain a test bay, between 45m and 60m long, is selected and divided
into three equal sections of length d, A staff is set up on an iron ground plate
or peg at each of the intermediate points B and C (if only one staff is used it
must be moved as required from point B to point C).
The instrument is set up, in turn, over the terminal points A and D. With the
instrument at A-after centering the circular bubble and checking the
compensator with the press button – readings a1’ and a2 are taken to the
staffs held at B and C, with the instrument at D, readings a3’ (to C) and a4’ (to
B) are then taken. If the line of sight is absolutely horizontal, these readings
will be the correct readings a1, a2, a3, a4, respectively, and the following
relationship will be valid. As can be seen from the figure: a4 – a1 = a3 – a2
If this is not so, however, the line of sight is inclined to the horizontal plane by
the small angle, . If an imaginary line parallel to a1’ a2’, is projected throughδ
a3’, it will cut the staff at B in the correct position a4, thus giving the required
value for a true horizontal line of sight from D. This is seen quite plainly in the
figure.