Topcon LN-100 - CHECK; Setup and Measurement for Accuracy Check

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7. CHECK
LN-100 is a precision instrument. It must be inspected before use so that it always performs accurate
measurements.
In addition, the instrument should be inspected with special care after it has been stored a long time,
transported, or when it may have been damaged by a strong shock.
 Setting Up the Instrument
Perform a setup operation under an environment where the sunlight is weak and not fluctuating
as well as LN-100 and the targets can be set as illustrated below.
• To perform checking efficiently, mark the four points described below using setting-out function
in advance.

• Place the instrument and targets in a straight line when looking from directly above.
• Acceptable range of each point position is ±5cm in all directions.
• Set LN-100 and the targets on a substantially horizontal place (such as a floor, level ground,
tripods of the same height). (The guideline for difference in height at 30 m is about 30 cm)
• Use ATP2 (360° prism) or ATP2S (360° slide prism) for the target.
• To set ATP2S, lower the height of the prism to reduce the setting error.
 Measurement

• Sighting can be more accurately performed by facing the ATP2/ATP2S toward the instrument.
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ATP2 : The 360° Prism should be set up so that a pair of diametrically-opposed hexagonal
points on its rubber flanges are aligned with the sighting direction of the instrument
(see the diagram below).
ATP2S : The 360° Prism should be set up so that a pair of diametrically-opposed marks on
top of the prism are aligned with the sighting direction of the instrument.
: Hexagonal points
: Prism sighting direction