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.
Instruments equipped with an ATR sensor permit automatic angle and distance
measurements to prisms. The prism is sighted with the optical sight. After ini-
tiating a distance measurement, the instrument sights the prism centre auto-
matically. Vertical and horizontal angles and the distance are measured to the
centre of the prism. The lock mode enables the instrument to follow a moving
prism.
As with all other instrument errors, the collimation error of the automatic aim-
ing must be redetermined periodically. Refer to "5 Check & Adjust" about
checking and adjusting instruments.
When a measurement is triggered while the prism is still moving, distance and
angle measurements may not be made for the same position and coordinates
may vary.
If the prism location is changed too quickly, the target may be lost. Make sure
that the speed does not exceed the figure given in the technical data.
☞
☞
ATR/Lock
☞
☞
☞
Operation
43
