Accuracy Check of the Measuring
Tool
Influences on Accuracy
■ The ambient temperature has the
greatest influence. Especially temperature
differences occurring from the ground
upward can divert the laser beam.
■ Because the largest difference in
temperature layers is close to the ground,
the measuring tool should always be
mounted on a tripod when measuring
distances exceeding 20m. If possible, also
set up the measuring tool in the center of
the work area.
■ In addition to external influences, device-
specific influences (e.g. falls or heavy
impacts) can also lead to deviations. For
this reason, check the levelling accuracy
each time before beginning work.
■ Firstly, check the levelling accuracy of the
horizontal laser line and then the levelling
accuracy of the vertical laser lines.
■ Should the measuring tool exceed the
maximum deviation during one of the tests,
please have it repaired by a Flex after-sales
service.
Checking the Horizontal Levelling Accuracy
For this check, a free measuring distance of 5
m on a firm surface between two walls A and
B is required.
Mount the measuring tool onto a tripod,
or place it on a firm and level surface
close to wall A. Switch on the measuring
tool to operation with automatic levelling.
Select the operating mode in which a
horizontal laser plane as well as a vertical
laser plane in front of the measuring tool
are generated. (Fig.H1)
Direct the laser against the close wall A
and allow the measuring tool to level in.
Mark the centre of the point where the
laser lines cross each other at wall A
(point I). (Fig.H2)
Turn the measuring tool by 180°, allow it
to level in and mark the cross point of the
laser lines on the opposite wall B (point II).
Without turning the measuring tool,
position it close to wall B. Switch the
measuring tool on and allow it to level in.
(Fig.H3)
20
Align the height of the measuring tool
(using a tripod or by underlaying, if
required) in such a manner that the
cross point of the laser lines is projected
against the previously marked point II on
the wall B. (Fig.H4)
Without changing the height, turn around
the measuring tool by 180°. Direct it
against the wall A in such a manner
that the vertical laser line runs through
the already marked point I. Allow the
measuring tool to level in and mark the
cross point of the laser lines on the wall A
(point III).
The difference d of both marked points
I and III on wall A results in the actual
height deviation of the measuring tool
alongside the lateral axis.
On the measuring distance of 2 x 5 m = 10m,
the maximum allowable deviation is:
10m x ±0.3 mm/m = ±3 mm.
Thus, the difference d between points I and III
must not exceed 3 mm (max.).
Checking the Levelling Accuracy of the Vertical
Lines
For this check, a door opening is required
with at least 2.5 m of space (on a firm surface)
to each side of the door.
Position the measuring tool on a firm,
level surface (not on a tripod) 2.5m
away from the door opening. Switch on
the measuring tool to operation with
automatic levelling. Select an operating
mode in which a vertical laser plane is
generated in front of the measuring tool.
(Fig.H5)
Mark the centre of the vertical laser line at
the floor of the door opening (point I), at
a distance of 5 m beyond the other side
of the door opening (point II) and at the
upper edge of the door opening (point III).
(Fig.H6)
Rotate the measuring tool by 180° and
position it on the other side of the door
opening directly behind point II. Allow
the measuring tool to level in and align
the verticallaser line in such a manner
that its centre runs exactly through points
I and II.
Mark the centre of the laser line at the upper
edge of the door opening as point IV.
ALC 3/360-G/R 10.8