4 Setup
l
At any time when the highest accuracy positions are required
l
Routinely on a periodic basis (Monthly, weekly etc.)
Spectra Geospatial also recommends that the operator keep a record of the dates and values measured
so that any gross changes can easily be detected. Gross changes can indicate the need for a check by
an approved service center.
In all calibrations, multiple sightings will be made in both faces to ensure that any minor pointing errors
can be eliminated in the accurate determination of current collimation error values. All measured
collimation and calibration values are stored and used until a new set of values are determined.
In a new instrument the values should be close to zero, over time these will change.
Compensator
Before starting the routine, level the instrument. An internal instrument battery must be present in the
side battery compartment. For instruments with Face 1 battery option, this battery compartment must
be empty. The instrument will automatically check if the compensator is within range before the
calibration is started.
The calibration process involves the instrument automatically reading the compensator value at a series
of predetermined positions through the full rotation of the instrument. The process takes approximately
one minute to complete. During the process the instrument should be on a stable platform, free from
vibration and untouched by the user.
Optical (HA/VA) Collimation and Trunnion Axis Tilt
The FOCUS 35 Total Station instrument utilizes precise angle and distance measurements to determine
the position of the point being measured. The instrument’s design facilitates the ability to measure all
points with a single pointing to the target in the Face1 position. All electronic total stations are subject to
collimation errors in both the horizontal and vertical angle measuring systems, and also errors caused by
the axis of the telescope not being truly perpendicular to the vertical of the instrument.
In order to compensate for these errors, the collimation routine allows the operator to accurately
determine the current errors in the instrument, and store the errors as corrections to be applied to all
measurements made in a single pointing to a target. In this way the FOCUS 35 Total Station will always
provide accurate measurements.
The adjustment of the instrument for HA/VA collimation and Trunnion Axis tilt is a two stage process.
LockNGo Tracker
Only on Instruments with LockNGo capability:
The LockNGo Tracker unit is designed to be coaxial with the instrument cross hairs. If for any reason the
alignment of the tracker deviates from the line of the telescope cross hairs, then errors in position of
the point being measured would result. For this reason an LockNGo collimation check needs to be
carried out on a regular basis to ensure that any slight misalignment is corrected for. Perform the test
over a similar distance as that you will be working on, but at least 100 m (328 ft).
FOCUS 35 Total Station User Guide |
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Summary of Contents for Focus 35
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