SOUTH
ET
‐
02/05
ELECTRONIC
THEODOLITE
SERVICE
MANUAL
2
SOUTH
SURVEY
&
MAPPING
INSTRUMENT
CO.,
LTD.
2
The structure of Electronic Theodolite
The ET of this series includes telescope, vertical encoder disk, horizontal encoder disk, electronic reading
system, plate level, vertical axis, horizontal axis, horizontal clamp and tangent screw, vertical clamp and
tangent screw, optical plummet, base and so on.
A. Telescope Unit
The telescope unit includes three parts: eyepiece, object lens and focuser. It has outside-focusing-style which
demands cozy and flexible rotation with no block and no sway. The eyepiece unit consists of eyepiece and
reticle unit.
B. Horizontal Axis Unit
The horizontal axis unit includes horizontal axis, its axletree and other sections. The horizontal axis should be rotated
flexible, at the same time, it should be vertical to the vertical axis and position is unchangeable in axletree during rotate.
Vertical encoder disk is on the left of horizontal axis, the telescope and cursory collimator are on the middle of it.
Sliding ring is on the right of horizontal axis.
In structurally, the vertical encoder disk should be assembly in correct position according following requirements:
a. the encoder disk centre and the horizontal axis centre must be positioned at the same point.
b. the reticle board of the vertical encoder disk must be perpendicular to the horizontal axis.
C. Handgrip Unit
The handgrip unit, convenient for carrying or laying, is fixed on the left and right brackets with two
setscrews.
D. Sighting Collimator Unit
The sighting collimator unit, for collimating the target at the beginning step, are fixed on the connection of
the telescope and middle of the horizontal axis. On the side of the object lens, there will be plane glass of
“+” or “
△
” type; while on the other side (the side of eyepiece), there will be a magnifier through which
“
△
”or “+” can be seen distinctly. Sighting collimator unit and the EDM axis must be coaxal.
E. Vertical Axis Unit
The vertical axis unit consists of vertical axis, sheath axis, horizontal encoder disk, CCD bracket, low cover
etc. This unit enables telescope, alidade and CCD photoelectric sensor to rotate horizontally in a vertical
way. Vertical axis unit is a half-athletic cylinder.
F. Vertical Clamp and Tangent Unit
It consists of clamp hand wheel, tangent hand wheel, clamp ring, clamp and tangent sheath, clamp and
tangent filar pole, versatile sheath, etc.
The clamp unit, clamped by the clamp ring, clamp block, and cam block, rotates around the clamp and
tangent filar pole and thus the clamp and tangent hand wheel works on the same axis.
