Topcon Automatic Level AT-B3

Center the bubble in the circular level

Turn the nearest leveling screw to the sighting axis 1/8 of a turn to the right or left

Check the movement of the horizontal cross-line

Cross-line should bounce, then immediately return to the original position

It is advisable to check the movement of the automatic compensator before use

Sign off on the automatic compensator adjustment

Set the instrument halfway between two points, A and B, 30 to 50m apart

Set the instrument at a point 2 m from point A

Calculate: b₂′ = a₂ - (a₁ - b₁)

If b₂′ ≠ b₂, proceed to adjustment

Adjust the leveling foot screws to center the bubble in the circular level

Turn the instrument 180° (or 200 gon)

Is the bubble inside the circle?

If the bubble is not inside the circle, proceed with the following steps

Compensate for one-half of the shift by adjusting the leveling foot screws

Eliminate the remaining half shift with the circular level adjusting screws using the hexagonal wrench

Turn the instrument 180° (or 200 gon) again

Is the bubble remains in the circle?

If the bubble remains in the circle, adjustment is complete