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INSTRUCTION MANUAL

AUTO LEVEL

AT-G4

AT-G6

Foreword

Thank you for purchasing the TOPCON GREEN LABEL Auto Level AT-G Series.
For the best performance of the instruments, please read these instructions 
carefully and keep them in a convenient location for future reference.

General Handling Precautions

• Before starting work or operation, be sure to check that the instrument 

is functioning correctly with normal performance.

Display for safe use

In order to encourage the safe use of products and prevent any danger to the 
operator and others or damage to properties, important warnings are put on the 
products and inserted in the instruction manuals.
We suggest that everyone understand the meaning of the following displays and 
icons before reading the “Safety Cautions” and text.

1) Injury refers to hurt, burn, electric shock, etc.
2) Physical damage refers to extensive damage to buildings or equipment 

and furniture.

Display

Meaning

WARNING

Ignoring or disregard of this display may lead to death or 
serious injury.

CAUTION

Ignoring or disregard of this display may lead to personal 
injury or physical damage to the instrument.

Safety Cautions

WARNING

• Cause eye injury or blindness.

Do not look at the sun through a telescope.
It is suggested to pay care specially at the time the position of the sun is 
low such in the morning or evening, or at the time the sunlight is coming 
directly to the objective lens of the instrument, cut off the sunlight by your 
hand or use an umbrella in such case.

• Do not use the staff in conditions of thunder and lightening.

As this is an electric conductor, thunderbolt can cause serious injury or 
death.

• Keep the staff away from electric facilities such as a high voltage 

wire or substation.

As this is an electric conductor, there is danger of electric shock.

CAUTION

Risk of injury by overturn the carrying case.
Do not stand or sit on the carrying cases.

User

Please note that the tips of tripod can be hazardous, be aware of this 
when setting up or carrying the tripod.

Risk of injury by falling down the instrument or case.
Do not use a carrying case with a damaged which belts, grips or latches.

A plumb bob can cause an injury to a person if used incorrectly.

Ensure that you mount the Tribrach correctly, failing to do so may result in 
injury if the tribrach were to fall over.

It could be dangerous if the instrument falls over, please check that you 
fix the instrument to the tripod correctly.

Risk of injury by falling down a tripod and an instrument.
Always check that the screws of tripod are tightened.

1) This product is for professional use only!

The user is required to be a qualified surveyor or have a good knowledge of surveying, 
in order to understand the user and safety instructions, before operating, inspecting or 
adjusting.

2) Wear the required protectors (safety shoes, helmet, etc.) when operating.

Exceptions from Responsibility

 Standard set component

1) The user of this product is expected to follow all operating instructions and make 

periodic checks of the product’s performance.

2) The manufacturer, or its representatives, assumes no responsibility for results of a 

faulty or intentional usage or misuse including any direct, indirect, consequential 
damage, and loss of profits.

3) The manufacturer, or its representatives, assumes no responsibility for consequential 

damage, and loss of profits by any disaster, (an earthquake, storms, floods etc.).
A fire, accident, or an act of a third party and/or a usage any other usual conditions.

4) The manufacturer, or its representatives, assumes no responsibility for any damage, 

and loss of profits due to a change of data, loss of data, an interruption of business etc., 
caused by using the product or an unusable product.

5) The manufacturer, or its representatives, assumes no responsibility for any damage, 

and loss of profits caused by usage except for explained in the user manual.

6) The manufacturer, or its representatives, assumes no responsibility for damage caused 

by wrong movement, or action due to connecting with other products.

Model AT-G4 or AT-G6  ............................ 1each
Plastic carrying case ................................ 1each
Lens cap  .................................................. 1each
Plumb bob set........................................... 1each
Hexagonal wrench.................................... 1each
Silicon cloth .............................................. 1each
Vinyl cover ................................................ 1each
Instruction manual .................................... 1each

Specifications

Telescope

Overall length ............................................. 192mm(AT-G4)

193mm(AT-G6)

Image ......................................................... Erect
Effective diameter lens ............................... 30mm
Magnification .............................................. 26X(AT-G4)

24X(AT-G6)

Field of view ............................................... 1°30'
Resolving power ......................................... 3.5"(AT-G4)

4"(AT-G6)

Minimum focus ........................................... 0.5m

Horizontal circle

Diameter ..................................................... 117mm
Minimum reading ........................................ 1°

Automatic compensation mechanism

Range

.............................................. ±

15'

Measuring accuracy

1 km double run

.................................. ±

2.0mm

Circular level

Sensitivity ................................................... 8'/2mm

Other

Protection against water and dust .............. IPX7
(Based on the standard IEC60529)

Weight

Instrument .................................................. 1.6kg
Plastic carrying case .................................. 1.3kg

Nomenclature

Focusing knob

Circular level viewing prism

Sighting collimator

Eyepiece

Base plate

Leveling screw

Horizontal circle

Objective lens

Horizontal knob

Circular level

Operating

Setting

1

First position the tripod leg and then 

spread the other two so as to make 

the tripod head almost level.

2

Firmly position the tripod legs on the 

ground, then tighten the screws.

3

Place the instrument on the tripod 

head, then screw the tripod screw 

into the instrument bottom for secur-

ing it to the tripod.

4

Use a plumb bob to match the instru-

ment center with the measuring point 

when a horizontal scale is used.

5

Use the three leveling screws to cen-

ter the circular level. When a dome 

head tripod is used loosen the tripod 

screw a little, slide the instrument, 

center the bubble, looking at the 

level, then the tripod screw to secure 

the instrument.

Tripod head

Tripod 
screw

Adjuster

Plumb bob

Measuring point

Fixing 
screw

Leg

Leveling 
screw

Collimating

1

Direct the telescope to bright object 

and turn the eyepiece ring so that the 

reticle in the telescope is clearly seen.

2

Turn the instrument manually and 

align the target through the sighting 

collimator.

3

Focus the target with the focusing 

knob.

4

Turn the horizontal knob to match the 

reticle with the target.

Measuring (Height)

In order to measure the difference in height 
between point A and point B.

1

Set up the instrument almost in the 

middle of the points.

2

Provide a leveling rod at point A and 

B, one each, collimate them and read 

the horizontal line of the reticle.

3

Suppose the reading at point A is a 

and that at point B id b, and the differ-

ence in height between the two points 

will be: a - b

Circular level

Target

Collimator

AT-G4(E).fm  Page 1  Thursday, September 7, 2006  2:20 PM

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