Additive Distance Constant - Sokkia SET2CII Operator's Manual

23. CHECKS AND ADJUSTMENTS
23.7 Additive distance constant
The additive distance constant K of the SET2C is adjusted to 0
before delivery. However,
it
may change over time and so should
be determined periodically and then used to correct distances
measured.
(Chet.L>
1) Select pointsA and B o n flat ground about 100 m (328ft) apart, and
C in the middle.
Note: Ensure that the target height is the same as the instrument
height of the SET2C objective lens centre. If the ground is not
flat, use an automatic level to set the correct instrument
heights of all points.
About 100m
A C B
2) Set u p the SET2C at A, the target at B and measure (fine mea-
surement) of the distance A-B 10 times.
3) Shift the SET2C to C, and measure (fine measurement) of the
distance C-A and C- B 10 times each t o targets at A and B.
- -
4) Calculate the averages of A-B, C-A a n d r ~ .
5 ) Compute the additive distance K using the formula:
-
-
-
K = A - B
-
(C-A+ C-B)
Obtain the
K
value several times. If all K values are greater
than
i 3 m r n , please contact your Sokkia agent.
Note: Errors in setting up the instrument and sighting the target will
affect the determination of the additive distance constant,
therefore perform these procedures as carefully as possible.
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