SHANGHAI ESURVEY GNSS CO., LTD.
20
9. Rotate the instrument in the right position, and make the reading is HA2' = HA2 + C.
10. Remove the eyepiece cover to adjust the two horizontal adjusting screws until the
reticle coincides with the reticle of collimator or the target:
11. Repeat the whole process of checking and adjusting the collimation error until the
error is less than or equal to 8''.
5.7
Check and Adjust the Vertical Index Error
The deviation between vertical circle zero position and horizontal direction is vertical index.
It is necessary to concern this error when measuring vertical angle.
Because of the close relationship between vertical index and compensator zero position, it
is necessary to check and adjust compensator zero position when adjusting the vertical
circle, to keep the value stable when reading.
To check and adjust the vertical index error, do the following:
1. Set the instrument on the tripod or the calibration stand, and precisely level it.
2. Enter angle measurement after powering on the instrument.
3. Aim at target A. The vertical angle shows (VA1).
4. Rotate the instrument 180°.
5. Aim at target A again. The vertical angle shows (VA2).
6. Calculate the vertical index error:
C = (VA1 - VA2 ± 360°) / 2
7. Judge if the error is within the allowable range:
o
If it is less than or equal to 10'', no adjustment is required.
o
If it is greater than 10'', proceed to step
8
-
12
.
