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instrument is over 3′, which is over the range the instrument
was designed to compensate. Screw the leveling screw back
towards the opposite direction, the vertical angle re-appears on
the screen. It shows that the tilt works well now. Users may
observe the change of the readout about the critical point.
Calibration
When finding the tilt compensator abnormal, please send
the instrument back to factories for servicing.
11.6 Vertical index error (angle i) and set vertical index 0
Please first adjust finely the reticule of the telescope and
the tilt compensator before calibrating and checking index
error.
Check
1. Turn on the instrument after placing and leveling it.
Aim at any clear target A with the telescope and readout the left
vertical angle L.
2. Turn the telescope around and aim at the same target A
and readout the right vertical angle R.
3. Assume that the zenith of the vertical angle is 0°, then
angle i= (L+R-180°)/2 OR
Angle i= (L+R-540°)/2
4. If the absolute value of I is greater or equal to
10″(|i|≥10″), it will be necessary to set 0 for the vertical index.
5. The following steps see reference in 9.6.1.