Spectra LL300-2 User Manual

9

In order to avoid offset errors, the receiver should be used close to the elevation where the laser has been 
set up.

If a remote control is available, the up and down arrow buttons can be used for fi ne adjustments.

The overall accuracy of the unit can be infl uenced by many factors:
• factory accuracy;
• temperature of the unit;
• ambient infl uences like rain, wind and temperature.
The factor that infl uences on the unit’s accuracy most is the ambient temperature. Vertical differences in 
temperature near the ground can divert the laser beam, similar to the heat waves seen on hot asphalt 
streets.

This factor also applies to all optical measuring  devices  such as automatic levels and 
theodolites.

To ensure job-site accuracy, you need a distance of 20 m (65 feet) 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 plus X-axis pointing towards wall A. 
After the unit is level, mark the height of the laser beam using a receiver at wall A. Turn the entire unit 180°, 
let it self-level and mark the center of the laser beam at wall B. 

A

B

20m

1

1.1

1.2

Now, place the unit near wall B with the plus X-axis pointing towards wall B. After the unit is level, mark the 
height of the laser beam at wall B. Turn the entire unit 180°, let it self-level and mark the center of the laser 
beam at wall A. The difference (h) of the marked points at wall A shows the deviation. 

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17.09.2004, 11:43:56 Uhr