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☞
Summary of errors to
be adjusted
electronically
5.2
☞
☞
☞
☞
44
During the manufacturing process, the instrument errors are carefully determ-
ined and set to zero. As mentioned above, these errors can change and it is
highly recommended to redetermine them in the following situations:
Before the first use
•
Before every high precision survey
•
After rough or long transportation
•
After long working periods
•
After long storage periods
•
If the temperature difference between current environment and the tem-
•
perature at the last calibration is more than 20 °C
Instrument
Effects
error
Hz
c - Line of sight
ü
error
a - Tilting axis
ü
error
l - Compensator
–
index error
t - Compensator
ü
index error
i - Vertical index
–
error
ATR Collimation
ü
error
Preparation
Before determining the instrument errors, the instrument has
to be levelled using the electronic level.
The tribrach, the tripod and the underground should be stable
and secure from vibrations or other disturbances.
The instrument should be protected from direct sunlight to
avoid thermal warming.
It is also recommended to avoid strong heat shimmer and air
turbulence. The best conditions are early in the morning or
with overcast sky.
Before starting to work, the instrument has to become acclimatised to the
ambient temperature. Take at least 15 minutes into account or approximately
2 minutes per °C of temperature difference from storage to working environ-
ment.
Even after adjustment of the ATR, the crosshairs may not be positioned
exactly on the centre of the prism after an ATR measurement has been com-
pleted. This outcome is a normal effect. To speed up the ATR measurement,
the telescope is normally not positioned exactly on the centre of the prism.
Effects
Elimination
V
with two face
measurement
–
ü
–
ü
ü
ü
–
ü
ü
ü
–
ü
Automatically
corrected
with proper
adjustment
ü
ü
ü
ü
ü
ü
Check & Adjust
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