Spectra Precision Focus 30 User Manual

6 Instrument Technology
76 Spectra Precision FOCUS 30 User Guide
Correction for Trunnion Axis
The trunnion axis tilt error is the deviation of the trunnion axis of the telescope from
its required position at right angles to the plumb axis of the instrument, see Figure 6-
1.
Fig. 6-1 Trunnion axis tilt error
Trunnion axis
tilt error
In the Spectra Precision FOCUS 30 Total Station, perform a pre-measurement trun-
nion axis tilt test to determine the trunnion axis ti
lt error. Angular measurements are
observed in both instrument faces, the trunnion axis tilt error is calculated, and the
respective correction value is stored in the instrument. The trunnion axis tilt correc-
tion value is then applied as a correction to the horizontal angle
value.
Carry out a trunnion axis tilt test
in the following situations:
• Whenever the instrument may have been roughly handled during transport.
• When the ambient temperature differs by more
than 10°C (18°F) from the
previous collimation test.
• Immediately prior to high precision
angle measurements in one face.

Spectra Precision Focus 30 Specifications

General

Brand	Spectra Precision
Model	Focus 30
Category	Measuring Instruments
Language	English