Distance measurement
When measurements are being made using the red laser EDM, the results can be influenced by objects passing between the EDM and the intended target surface. This occurs because reflectorless measurements are made to the first surface returning sufficient energy to allow the measurement to take place. For example, if the intended target surface is the surface of a building, but a vehicle passes between the EDM and the target surface as the measurement is triggered, the measurement may be made to the side of the vehicle. The result is the distance to the vehicle, not to the surface of the building.
➜ Accurate measurements to prisms should be made in prism mode.
➜ When a distance measurement is triggered, the EDM measures to the object which is in the beam path at that moment. If a temporary obstruction, for example a passing vehicle, heavy rain, fog or snow is between the instrument and the point to be measured, the EDM may measure to the obstruction.
➜ Do not measure with two instruments to the same target simultaneously to avoid getting mixed return signals.
ATR
Instruments equipped with an ATR feature permit automatic angle and distance measurement to prisms.
The prism is sighted with the optical sight by the user.
After initiating a distance measurement by the user, the instrument will aim to the prism centre automatically.
Vertical and horizontal angle and the distance are measured to the centre of the prism.