Topcon DS-101AC, Instruction Manual

Page: 58 / 176

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10.TARGET SIGHTING
A target can be automatically sighted using the Auto Pointing function or manually sighted by the
operator using the sighting collimatorand telescope.
When Auto Pointing is performed, the image sensor on the
instrument detects the light beam reflected from the target (prism
or reflective sheet target), the offset between the target and
telescope reticle is calculated by image processing, then the angle
measurement value obtained from the encoder is compensated.
There is a possibility that the target and telescope reticle are not
aligned.
C
Caution
• The instrument emits a laser beam until the prism is sighted.
G
• Auto Pointing can only be performed when a prism or sheet is used as the target. For reflectorless
measurement, the target must be sighted manually.
• Use designated reflective prisms/reflective sheets for higher precision measurement. Make sure
reflector type and aperture/sheet size are set correctly in <EDM configurations>.
• Detach the handle if the prism is located at the zenith.
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"4.1 Parts of the Instrument Handle
L
Detaching/attaching the Handle"
• Auto Pointing may take long time if the prism is located at the zenith. In this case, use optional
accessory diagonal eyepiece (DE27) and manually sight the target.
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"10.3 Manually Sighting the Target"
• If more than one prism is located in the field of sight during Auto Pointing, an operation error will
occur and the instrument will not be able to find the target.
• A prism beyond glass cannot be searched because a measurement error occurs.
• If an obstacle blocks the laser beam path between the instrument and the prism, instrument cannot
find the target correctly.
• If strong light shines directly into the objective lens, measurement cannot be performed correctly.
• Position every target in alignment with the objective lens to eliminate the error caused by tilted
target.
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Facing the 360° prism toward the instrument: "26.1 High Accuracy with the 360° Prism"
• The following table suggests what size target to use for different distances when performing Auto
Pointing with a reflective sheet target.
Distance Target size
5 to 15m RS10 (10mm)
5 to 30m RS30 (30mm)
5 to 40m RS50 (50mm)
10 to 50m RS90 (90mm)
Offset
of X direction
Of
fset
of Y
direction