GPI NP-732 Series Instructions For Use Manual

Automatic Level

NP-732

INSTRUCTIONS FOR USE

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Contents

Before use…………………………………………………2

1.Nomenclature.………………………………………………3

2.Operation…………………………………...……………….4

2-1 Preparing before surveying……………………….……….….4
2-2 Surveying method………….…………...………...……..…….5

2-2-1 Measuring altitude difference……………………………..….5
2-2-2 Measuring horizontal angle…………………………………..7

2-2-3 Measuring distance using the stadia lines…………..……….7

3.Regular checking/ adjusting………………………..……..……9

3-1 Checking and adjusting of the circular level……………..…9

3-2 Checking of the compensator………………………………...10

3-3 Checking of i angle…………………………………….….....10

4.Parameter and technical index……………………………12

5.Standard configuration………………...………………….12

NP-732 SERIES

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Before use

1 Operation

1) The NP-732 series automatic level is a precision instrument. Handle

it carefully according to the engineering measurement regulations,
and keep it away from heavy shocks and vibration.

2) Never place the instrument directly on the ground to avoid damage to

the base surface or thread.

3) Before using, please check thecompensator.

2 Maintenance

1) Use a neutral cleaning or water to clean the horizontal circlescale

window and the instrument, never use an organic solvent.

2) Use optical lens tissue to clean the objective and the eyepiece

carefully.

3) Do not take down or assemble it yourself that is not mentioned in this

manual.

4) After use, store it in a container to prevent dust, and put it in a dry

and clean place.

5) In order to keep the high precision of the instrument, appraise the

instrument regularly one or two times a year.

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1. Nomenclature

NP-732 SERIES

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2.Operation

2-1 Preparing before surveying

(1) Spread the tripod-legs so that the leg-tips form a regular triangle.

Extend the legs until the tripod head is roughly at 10cm lower than
your eye level and then fasten the extension clamp screws.

(2) Make sure that the tripod head is approximately level. Stamp the

tripod-feet firmly into the ground.

(3) Set the automatic level onto the tripod head and tighten the

center-screw.

(4) If using a spherical-head tripod, loosen the center screw and hold the

base plate, then let the level to slide on the spherical-head tripod and
get the bubble in the center (See fig.1).

(5) Fasten the center-screw.
(6) Adjust the three leveling screws to get the bubble in the center (See

fig.2).

Fig.1

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2.Operation

(7) Adjust the eyepiece until the image of the reticle is clear.

(8) Aim the objective at the staff through the sight gage of the

instrument.

(9) Turn the focusing knob to get the staff image very clear. Shift your

eyes around in the field of view and make sure that there is no
displace between the reticle and the staff, then the surveying and
reading can be done. Adjust horizontal fine moving knob to aim the
telescope at the target.

2-2Surveying method

2-2-1Measuring altitude difference

(1) Set up the instrument at a point approximately halfway between

points A and B. (See fig.3)

Fig.2

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2.Operation

(2) Set up the staff vertically at point A, and take the reading a

(backsight).

(3) Set up the staff vertically at point B, and take the reading b

(foresight).

(4) The altitude difference h from B to A is h=a-b.
(5) If the distance between A and B is too long, or the altitude

difference from B to A is too large, divide the distance into some
regions, then carry on measuring in each region. (See fig.4)

Fig.3

Fig.4

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2.Operation

Calculation of altitude difference as follow:
Altitude difference=Sum of backsight-Sum of foresight

Altitude of the surveying point=Altitude of known point+Altitude
difference

2-2-2Measuring horizontal angle

The horizontal-circle-scale is graduated in minimum value of 1°and

numbered every 10°.

(1)Use the plumb-bob to set the center of the instrument right above the

surveying point.

(2)Aim the telescope at point A and set the horizontal-circle-scale to 0°

by turning the horizontal circle positing ring.

(3)Aim the telescope at point B and take the angle reading. It’s the angle

of position between A and B.(See fig.5)

2-2-3Measuring distance using the stadia lines

Using the top and bottom stadia lines on the reticle, the distance
between the center of the instrument and the staff can be measured
approximately. Aim the telescope at the staff, read the number of

Fig.5

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2.Operation

centimeters on the staff between two stadia lines, then transform it
into number of meter by multiplying 100, and the number of meter is
the distance between the center of instrument and the staff. (See fig6)

Fig.6

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3.Regular checking /adjusting

3-1 Checking and adjusting of the circular level

(1)Adjust the leveling screws to center the bubble in the circular level.
(2)Turn the instrument 360°. If the bubble is still in the center, it means

that the circular level is workable.

(3)If the bubble shifts away from the center, please adjust according to

following methods:

Move the bubble one half of the shift to the center of the circular level
by adjusting the leveling screws. Then get the bubble in the center of
the circular level by adjusting the circular level adjust-screw with the
hexagonal wrench. Repeat the above checking and adjusting, until the
bubble does not shift when the instrument turns to any direction. (See

fig.7)

3-2 Checking of the compensator

(1)Center the bubble in the circular level, and aim the telescope at a

target about 70m away.

(2)Turning the leveling screws to make the bubble slide out about 1/4 of

the circular to any direction, if there is no deviation between the image
of target and the horizontal cross-lines, it means that the working range

Fig.7

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3.Regular checking/adjusting

and the precision of the compensator are stable. This checking must be
done before surveying.

3-3 Checking of i Angle

(1)Set up the instrument at a point halfway between points A and B, the

distance between staff A and staff B is about 50mm. Take reading a1
and b1. (See fig8)

(2)Set up the instrument at a point 2m from point A. Take the reading a2

and b2. (See fig.9)

Calculate: b2′=a2-(a1-b1), If b2′= b2, it means that the instrument is
workable, otherwise adjust the instrument as follows:

Unscrew and remove the cover for the reticle adjusting screw. (See

fig.10)

Use the adjusting pin to adjust the position of the cross line of reticle,

if b2′ b2, adjust downwards, otherwise, adjust upwards.(See fig11)
Repeat the adjustment until b2′= b2 or the difference is smaller than

4mm.

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3.Regular checking/adjusting

Fig.8

Fig.9

Fig.10

Fig.11

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4.Parameter and technical index

NP-732 Series(A model, B model)automatic level technical parameter

5.Standard configuration

Instrument Downy cloth Plumb bob
Incidental tool Operation manual Plastic case

Parts

Model

NP-732

Magnification

32X

Image

Erect image

Objective aperture

≥42mm

Min focusing distance

0.3m

Stadia multiplication

constant

100

Stadia additive constant

0

Resolution

≤4″

Telescope

Pattern of stadia reticle

Working range

±15′

Compensating error

≤±0.3″/1′

Compensa

-tor
Setting accuracy

≤±0.5″

Scale graduation range

360°/400g

Scale

Scale minimum value

1°/lgon

Sensitivity of circular bubble

8′/2mm

Base screw

M16 or 5/8″for option

Environmental temperature

-25℃ -+50℃

Carry case

Plastic case(Aluminum case for potion with extra

Parallel plate micrometer

Available for option

NP-732 SERIES

NP-732 SERIES

Giant Precision Instrument Co., Ltd.

No.16, Ln. 134, Liancheng Rd., Zhonghe Dist., New Taipei City 235, Taiwan

TEL [phone] FAX [phone]