User's Manual

12.8 CONSTANT K

The Instrument constant has been checked and adjusted in the factory, and K=0. It seldom changes

and it is suggested to check once or twice in a year.

Inspection

1. Mount and level the instrument on Point A on

flat ground. Use the vertical hair to mark Point B

and Point C with the distance of 50m on the

same line, and collimate the reflector accurately.

2. After setting temperature and pressure value,

measure the horizontal distance of AB and AC

accurately.

3. Setup the instrument on Point B and center it

accurately. Measure the horizontal distance of

BC accurately.

4. Then you can get the Instrument Constant:

K = AC - (AB + BC). The value of K should be close

to 0. If |K|>5mm, the instrument should be strictly

inspected on the base alignment, and be

adjusted according to the inspection value.

Adjustment

Set the orientation through the vertical hair to

make Point A,B, and C on the same line strictly.

There must be a fixed and clear centering mark

under the Point B.

The coincidence of the center of the prism and

the center of the instrument is very essential to

the measuring accuracy. Therefore, it’s best to

use a tripod or a common-used tribrach on the

point B. If we replace it with a three-foot adapter

and a tribrach, make sure that they are stable

and fixed. It is possible to reduce the

inconsistency if we just replace the upper part of

the prism and the upper part of the instrument.