PENTAX
AUTOMATIC LEVEL
L-M2 SERIES
AL-M2 - AL-M2c-AL-M2s
INSTRUCTION MANUAL
ASAHI PRECISION CO., LTD.
(For proper operation of instrument)
Pentax automatic level AL-M2 series consist of a variety of instruments in order
to comply with a wide range of surveying from second or third order leveling
surveying to civil engineering requiring high accuracy.
Our surveying instruments are precise in function and precision made. Survey-
ing instrurnents do not either work well nor become of value unless they are
carefully handled and operated. For the instrument to work efficiently and be
useful for long time, read through this instruction book.
Storage
This instrument should be stored in a dry, dust-proof room, which does not
have a big temperature range. When the instrument is stored for a long time, it
must occasionally be taken out of the case and air circulated freely around the
instrument. When storage or transportation temperature is extremely different
from the working temperature, the instrument must be allowed to coma to the
ambient temperature. Exposure time required is approximately one minute per
one degree temperature difference.
Transport
For shipment, the instrument should be packed with cushioning material with
reasonable thickness on all sides. Insurance coverage is recommended. Vehicle
transportation does not require packing but movement should be restricted
by securing it. When heavy vibration or rough travel is encountered, it is
recommended that the instrument be secured in a padded box.
Checking
Before measurement, an instrument should be examined according to this
instruction book. if necessary, the instrument should be adjusted. Even a new
instrument or completely repaired instrument needs to be checked. This proce-
dure is also recommended during long intervals of non-use or after long
journey. At least once per year, or more often, it is recommended that the
instrument should be checked by a qualified Pentax dealer.
Unpacking
When removing an instrument from its carrying case, pay attention to how it is
positioned so that it can be returned properly. Grasp the instrument securely
when removing or returning it from or to the case.
Setting up
When installing or removing the instrument on or from the tripod, the instru-
ment should be securely held with one hand while the other hand manipulates
tripod center screw. The instrument should never be left on the tripod without
being fastened down. Failure to carry out these instructions can result in a bad
accident. Careful operation and handling of the instrument in accordance
with these instructions and plain common sense will provide long and
useful service.
Contents
N A WON =
Features EEE 4
Description re ee 5
Equipment... RR RK a aa aa aa a aa a ALL 1240 6
Specifications ...... LLL eee 7
Operation
[1] Preparation for surveying
1) Setting up the tripod ............ a 8
2) Setting up the instrument .........e e. _eseederraeoa arras 8
3) Leveling vor ee ee ee aa 9
Observation
1} Reticle collimatign i i ieee 9
2) Sighting aa 10
3) Reading the staff ..........._..eeeeeeeceeresorereece a. 11
[3] Surveying
1) Leveling ...........eesmesrareee ea 00. a ea er acorecee 11
2) Stadia survey ...........e.eereedeeaareosaroaanaaaranrao, 12
3) Angle Measurement eee 13
Maintenance and packing
[1]|Maintenance .....22222 024442100200 4 ea era a aa aa a a a ea aa aa 0 14
ELA + A1 M i ee eee 14
Précaution ......220000000 00e e eee eee eee ee see eee ea a aa eee a are en 15
Inspection and adjustment
[1]Circular level co i ie 15
[2] Leveling line of sight ............. ci 16
Optional accessories
[1] Electric illumination [EP]... ..... a. 18
[2] Parallel plate micerometer [5M3] ...0.0000000000000 0400011010800 19
[3] Diagonal eyepiece [SBL1] .... iii ia 21
. Features
«=
NM Easy to operate due to simple design, and compact and light construction.
B The telescope is of dust — and water resistance, enabling use of the instru-
ment in the rain or tunnel with humidity.
H Minimum focus distance is extrernely short, 0.8m. Anallactic optics of the
telescope makes stadia surveying easy as the stadia constant is 0.
E With special alloy ribbon with long-established reputation, a newly
developed automatic compensator having magnet damper is of wire-
suspension type and provides extremely stable surveying results even
under unfavorable conditions such as vibration.
EH Optical collimator provides fast and accurate sighting.
E Concurved foot plate fits domed head tripod as well as flat-head tripod.
MB Adjustable reflecting prism permits operator to observe the circular level
without changing his operating position, thus enabling easy confirmation of
leveling.
m Clampless horizontal drive screw equipped with knobs on both ends pro-
vides endless movement of the telescope.
E AL-M2C with a horizontal circle permits horizontal angle measurement as
well as angle setting.
E AL-M?5 equipped with a glass circle graduated down to 10’ or 10c permits
angle measurement with higher accuracy. Fine-coarse focussing screw
provides fast and accurate focussing.
HB Electric illumination, parallel plate micrometer and diagonal eyepiece are
available as optional accessories.
2. Description
Collimator
Evepiece
i ar cover
Horizontal Eyepiece
drive screw lens
Foot plate Leveling
Fig. 1 screw
Circle rotation ring Circle reading window
(For AL-M2C, AL-M25 only) (For AL-M2C only)
Collimator Focussing knob Line of sight adjusting ring
Reflecting
prism
Circular bubble
Leveling screw Horizontal
drive screw
Fig. 2
Foot plate
Circle reading
eyepiece
Fig. 3 о (For AL-M25 only)
Equipment
[1] Standard Equipment
Instrument era aaa 1
Carrying case «oe eae + 1
Objective Cap E 1
SE A a ea eee ar ea ae a a a rareanederen 1
Plumb bob (AL-M2C, M25 only)... en 1
Screw NIVEL Le eee à 1
Adjusting Pins .. oo eae aa en 2
Brush aaa 1
Räin cover er eae 1
Silicone cloth «ooo ee 1
|2] Optional accessories
Tripod (T5-3) Parallel plate micrometer (5M3)
Electric illumination (EP) Diagonal eyepiece (SBL1)
4, Specifications
AL-M2 AL-M2C | AL-M2S
E Telescope (Internal Anallactic Optics)
Image Erecting
Magnification 32x
Objective aperture 45mm
Resolving power 2.5
Field of View 2.3% (2.3m at 100m or 2.3 feet at 100 feet) or 1°20’
Minimum focus distance 0.8m
Stadia ratio 1:100
Stadia constant 0
E Autornátic Compensator
Range +12"
Setting accuracy +0,3"
Standard deviation +1.0mm
1 km double run tevelling
E Circular level
Sensitivity 8'/2mm
E Horizontal Circle — metal glass
Diameter — 100mm 88rnm
Graduation — T’or1G 10’ or 10C
Reading method — Index Index
Least Reading — 1°0r 1G 10" or 10c
Estimation Reading — 0,1° or 0.1G 1’ ог 1с
Bm Tripod attaching screw
Thread 5/8" x 11
H Dimensions & Weight
Length 254mm
Width 140mm
Height 137mm
Weight 2.1 Kgs/4.6 Ibs 2.3 Kgs/5.0 Ibs
E Case 350 (L) x 210 (W) x 200 (H) mm, 2.5 Kgs/55 Ibs
Tripod TS-3 1~1.7m Length, 4.5 Kgs/9.9 Ibs
5. Operation
[1] Preparation for surveying
1) Setting up the tripod
( Prepare the tripod having a center locking screw with 5/8"x11 thread.
@) Dig the legs firmly into the ground and adjust the tripod to the height
suitable for observation when the instrument is mounted.
(3) For angle measurement, set the tripod so that the center of the tripod head
is positioned right above the ground point.
2) Setting up the instrument
(0 Mount the instrument on the tripod head and secure it using a center lock
screw. (Fig. 4)
® Suspend the plumb bob from the hook, adjusting the length of the string.
(for angle measurement)
G) Loosing the center lock screw, move the instrument with the tips of fingers.
Tighten it as a tip of plumb bob coincides with the ground point. (for angle
measurement)
Instrument
Foot plate
Tripod head
Center rock screw
Hook
Fig. 4
3) Leveling
(1) Place the telescope in parallel to the line connecting two optionally selected
leveling screws, and turn thern to move the bubble of the circular level at a
position even to the left and the right. (Fig. A)
B Turn the two leveling screws in opposite directions.
@ Turning a remaining leveling screw, shift the bubble to the center. (Fig. B)
(3) Make sure that the bubble stays at the center of the circle even after turning
the telescope 180°.
® See arrows in Fig. A and B for the relation between the direction of leveling
screw rotation and the bubble shifting direction.
EM {If the bubble is out of the center in (3), “adjustment of the circular level” on
page 15 is needed.
TT ey
FA / Telescope Leveling screw
A ©. À : > Parallel
“e
— Bubble” Bubble circle
Leveling screw
(A) Fig. 5 (B)
[2] Observation
1) Reticle collimation
(1) Remove the objective cap. If necessary, attach the sunshade.
(2) Directing the telescope to the bright background, rotate the eyepiece coun-
terclockwise to draw out the eyepiece ring.
(3) While looking into the eyepiece, rotate it clockwise until the cross hair of the
reticle comes to its extreme sharpness.
№ It is advisable to relax when looking into the eyepiece. An intense look at the
reticle may tend to cause parallax or eye fatigue.
Cross hairs
(A)
Fig. 6 Field of view
2) Sighting
(1) Sight the telescope at the object looking through the collimator.
(7) Looking into the eyepiece, rotate the focussing knob until the object be-
comes clearly visible. Make sure that the relation between the object and
the cross hair does not change even when you move your eye up or down-
ward. (Fig. 7)
Ef parallax exists in (2), the relation between the object and the cross hair
may change. This may cause surveying error.
Collimator
Focussing knob Object
Triangle mark
Telescope
eyepiece
(A) (8)
Fig. 7
3) Reading the staff
How to read the graduation on the staff.
Pa
Reading value 2.195m
Fig. 8
E Reading of the staff should be done at the center of the cross hair on the
reticle.
[3] Surveying
1) Leveling
# How to get the difference in height and the elevation
Difference in height (Ah) = backsight (b) — foresight (f)
Elevation at point B (ha) = Elevation at point A (ha) + Ah
S (1): Staff (I) S (11)
5 (TI): Staff (ID) 5 (1)
I: Instrument
B.S: Backsight (Staff reading
at the point where eleva-
tion is specified.)
Р.5: Foresight (Staff reading at
the point where elevation
is unspecified.)
Fig. 9 Datum level
Difference in height {AH} = EAN 1
= Eb — =f
Elevation He = Ha + AH
IT
EM Set the instrument at almost middle of two staffs.
E When reading the staff, try to get least reading by tilting the staff back and
forth slightly.
@ For more precise surveying, use the double run method.
2) Stadia survey
Distance from the instrument to the staff can be measured by the stadia hairs
visible within the field of view of the telescope.
NM To measure the distance is easy as stadia constant is 0.
S: Horizontal distance
¢: Difference in reading between of upper and of lower stadia lines
5=100 ¢
— |2 —
3) Angle measurement (axcept for AL-M2)
Models equipped with a horizontal circle are capable of horizontal angle mea-
surement or setting.
E Example
@ For AL-M2C Triangle mark Indexing line
84° 30°
Fig. 12
E When reading horizontal angle, be sure and put yourself just in front of it.
B Make use of symbol ¥ marked every 90° or 100G for right angle setting.
@ For AL-M2S
—
A ——
—
— rr
—
——]
—— a
= вари
ZELL
———
—
—
AT]
Pm. i di 127" 25
о До o Circle reading гв)
eyepiece
(A)
Fig. 13
13
6. Maintenance and packing
[1] Maintenance
(M) Clean dust or water from the instrument and then put it back to the case
after using it.
@) Brush dust off, wipe off moisture on exposed parts with a soft cloth.
(3 Wipe off the moisture on the surface of the lenses with a cotton cloth, using
light pressure, after brushing the dust off,
[2] Packing
(I) Gently put the instrument into the case, facing focussing knob toward you.
@ Close the case and secure thé latch.
Focussing
(A) knob
Fig. 14
7. Precaution
¿O Attach the sunshade to the telescope to avoid the direct sunlight when high
precise survey needed.
<> Operate the instrument carefully. Do not apply excessive pressure to it.
O Store the instrument in a dry place, removing dust or moisture after use of
it.
<> Be careful not to subject the instrument to impact or vibration during trans-
port.
<» When moisture or disorder is found inside the lens, contact your dealer, do
not attempt to dismantle the instrument by yourself.
<> When any malfunction due to falling down or some other cause is recog-
nized, contact your dealer, do not attempt to forcibly dismantle the instru-
ment by yourself.
<> Check all parts of the tripod are firmly secured.
8. Inspection and adjustment
[1] Circular level
1) Inspection
(1) Setting the instrument on the tripod, level it so that the bubble of circular
level is positioned at the center of the circle. (Refer to P.9 "Leveling”.)
@) Turn the telescope 180°
@) No further adjustment is necessary if the bubble stays at the center of the
circle.
2) Adjustment
(I) if the bubble moves out of the center in the circle, turn the leveling screw to
shift the bubble halfway back after taking off the reflecting prism. (Fig. A)
@ Shift the bubble remaining halfway to the center by turning adjustment
screws, (Fig. B)
(3) Turn the telescope 180° to check to see if the bubble stays at the center of
the circle. |
(4) Repeat again from (1) should the bubble move.
HE When doing adjustment, finish screws being firmly tightened.
Circle
Bubble
Adjustment
>© screw
Fig. 15
[2] Leveling line of sight
Target plate Approx. 2m
(A) Fig. 16 (B)
1) Inspection
(D Prepare two same target plates. Setting up the instrument midway between
two walls at a distance of 50 to 100 meters, level it. (Fig. 16(A))
@ Sighting both walls alternately, adjust the target plates to the height so that
readings of the target plates are identical, and secure them in position.
(3 Move the instrument to a position approx. 2 meters from one target plate
and level it. (Fig. 16(B))
(4) Read both target plates.
(5) No adjustment is necessary if readings of both target plates are identical.
2) Adjustment
(0 Sight the farthest target plate through the telescope.
@ Remove the eyepiece cover, rotate the reticle adjusting screw using the
adjusting pin and adjust the reading to be identical to that of the nearest
target plate.
(3) After checking that correct adjustment has been made, mount the
eyepiece cover back in place.
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— 17 —
9. Optional accessories
[1] Electric illumination [EP]
Electric illumination permits surveying work in a tunnel or any dark place by
way of illuminating the reticle.
Light source Green LED
Power supply . Two 1.5V dry batteries (SUM-3)
(D It can be mounted in the same way that a sunshade is attached to the tele-
scope objective.
@) Turn the switch on and adjust brightness by rotating illuminator knob while
looking into the telescope.
& Kemove battery when device will not be used for an extended period as
extended storage may cause damage to the device due to leakage of battery
acid.
Electric illumination
Reflex mirror
Mirror knob
[2] Parallel plate micrometer [SM3)
Parallel plate micrometer is used for leveling or civil engineering work
requiring precise accuracy. With a bright microscale etched on optical glass,
it provides reading down to 0.1mm.
HB Use the instrument with wedge type reticle for use of the parallel plate mic-
rometer.
E Replacement of the reticie if your instrument is equipped with ordinary
reticle should be made at your dealer,
Ш Use second order staff or equivalent to it, not ordinary one.
Operation
(1) Mount the parallel plate micrometer horizontally on the object and counter-
weight on the eyapiece of the telescope, respectively and secure both. (Fig.
19)
(2) Turning the micrometer knob, accurately put the staff graduation between
the wedge-shaped lines. (Fig. 20)
(3) Read the staff” and microscale’.
Counter weight Parallel plate micrometer
Clamp knob Micrometer knob
Fig. 19
(A) Staff (B) Microscale
Fig. 20
Example:
Staff reading 123.00cm
Micrometer reading 0.77cm
123.77cm
— 20 —
[3] Diagonal eyepiece (SBL1]
Diagonal eyepiece [SBL1] is to be used for surveying in a limited space or when
the instrument is set at a lower position where it is hard to look into the tele-
scope.
Operation
(I) Remove the eyepiece cover, turning it counterclockwise. (Fig. 1)
@ Screw the diagonal eyepiece in to the attaching screw of the eyepiece cover.
@ Looking into the eyepiece lens of the diagonal eyepiece, collimate the
reticle. (Fig. 21)
H Prior to attaching the diagonal eyepiece to the instrument, collimate the reti-
cle with eyepiece mounted on the telescope.
Eyepiece
Diagonal eyepiece
Fig. 21
— 21 —
PENTAX
ASAHI PRECISION CO., LTD.
Miyakezaka Bidg., 1-11-1 Nagata-cho,
Chiyoda-ku, Tokyo 100 Japan
Printed in Japan
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