Accuracy Check; Operating Examples; Marking Heights - Spectra 1452 Manual De Funcionamiento

Accuracy Check

To ensure job-site accuracy, you need a distance of 65 feet (20 m) between
two walls A and B, where you will execute 4 measuring operations on a
tripod as follows (transit measurement).
Set the unit horizontally on a tripod near wall A and switch it on with the X-
axis pointing towards wall A. After the unit is level, mark the height of the
laser spot at the centre of the beam at wall A. Turn the entire unit 180°, let
it self-level and mark the center of the laser spot at wall B.
1
A
1.1
Now, place the unit near wall B., with the X-axis pointing towards wall B.
After the unit is level, mark the height of the laser spot at the centre of the
beam at wall B. Turn the entire unit 180°, let it self-level and mark the
center of the laser spot at wall A. The difference (h) of the marked points at
wall A shows the deviation.
2
A
2.2
h
1.1
If the unit is within its working accuracy limits (± 21"), the maximum
difference from true level at 65 ft. (20 m) + 65 ft. (20 m) = 130 ft. (40 m) is
5/32 inch (4 mm). The highest and the lowest mark may be up to 5/16 inch
(8 mm) apart.
Repeat the above steps for "minus x" and for "plus-" and "minus y", so that
a measurement for all four axis of the unit have been performed.
If the visibility of the laser beam is bad, you can use a detector to transfer
the heights to the walls. The accuracy of the detector has to be regarded.

OPERATING EXAMPLES

Marking Heights

Put the instrument including prism in horizontal mode (e.g. when using a
tripod) so that the laser beam is at the desired height. Then either turn the
prism manually to the desired area or use one of the rotation modes.
When working without a tripod, put the instrument on a stable base and
measure the height difference between laser beam and desired height by
using a ruler. After turning the prism to the desired area, mark the measured
height again.
20m
B
1.2
B
2.1=1.2
15