Leica TS11 User Manual page 75

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 aiming
must be redetermined periodically. Refer to "4 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.
TS11/TS15, Operation 75