Spectra Precision Focus 30, User Manual

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4 Setup
52 Spectra Precision FOCUS 30 User Guide
Instrument Adjustment and Calibration
The chapter describes as instrument adjustments and calibration routines as well
adjustments for Laser Pointer see
page 57 , for Optical Plummet see page 61 and for
Tribrach Circular Level see page 62 .
These adjustments and calibrations will change over time, the most common changes
being caused by:
• Wear and tear with use
• Bumps and knocks during transit
• Large changes in operating temperature
Spectra Precision recommends that a collimation and calibration check be carried out
routinely as follows:
• After any long uncontrolled transport of the instrument (e.g. after service or
shipment to a new location)
• After any accidental knock or drop
• At any time when the operating temperature changes by more than 10 °C
(18 °F)
• At any time when the instrument changes it's height above sea level by more
than 500 m (1640 ft)
• At any time when the highest accuracy positions are required
• Routinely on a periodic basis (Monthly, weekly etc.)
Spectra Precision 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 colli-
mation 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 battery compartment. 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 compensa-
tor value at a series of predetermined positions through the full rotation of the instru-
ment. 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.