Newcon Optik LRB 20 000 - Manual (Page 10)

7.5.2. To orient the range finder by using the reference directional angle,
proceed as follows:
- Binocular the range finder on the reference point whose
directional angle has been known;
- rotate the azimuth dial to set the reference directional angle;
- turn the clamping handle to lock the azimuth dial in position.
With the range finder thus oriented, the measurements are taken from the
location point relative to the directional angle of the object (reference
object).
7.5.3. For the magnetic orientation of the range finder, proceed as
follows:
- unscrew the plunger knob all the way out to release the
magnetic needle of the compass;
- turn the AI about the vertical axis to obtain precise alignment of
the index mark of the circle with the magnetic needle;
- operate the azimuth dial to set the magnetic azimuth index
correction as specified in Section "Basic Specifications" 4 of
the present Operating instructions.
When using the compass to orient the range finder, bear it in mind that
the indexing accuracy of the magnetic needle is affected by the nearby
objects of iron or steel. See that motor vehicles, bulldozers and such like
objects are at least 10 m away, medium-size objects (pick hammers,
crows, etc.) are at least 0.5 m away, and small-size things (flash-light,
knife, screwdriver, etc.) are 20 cm away from the instrument.
7.6. To check the range finder for proper operation when using the AI and
the tripod:
- check the AI zero elevation reference (ER "0");
- check the AI compass.
- ER "0" is the setting of the elevation scale that corresponds to the
horizontal position of the range finder Binocular axis.
7.6.1. To check the zero elevation reference, proceed as follows:
-
stick a stake 50 to 100 m away from the unit and mark it with the
range finder objective height above the ground level;
- Binocular the reticle cross-hairs on the stake to read the tilt angle
(A1);
- swap the range finder and stake positions, and apply another mark
to the stake in accordance with the new height of the range finder
objective;
- Binocular the cross-hairs on the new mark of the stake and read
again the tilt angle (A2);
- find the ER "0" from the formula:
A1 + A2
ER "0" = ———— ,
2
The A1 and A2 values are reckoned in with their respective signs.
If the ER "0" value is other than zero, the respective correction is to be
taken into account while operating the range finder. The error value is
subtracted from the elevation measurement if on the positive side, and
added if negative.
7.6.2. To check compass, set up the AI for operation. Then, check the
sensitivity and balance of the needle.
For the purpose proceed as follows:
-
level the AI;
- uncage the needle;
- unbalance the needle by using a knife, screwdriver and the like.