Manual Chapter 5

6-7
Averaging - this mode of operation is intended to allow multiple sampling
of data in order to reduce the noise in the data by averaging all of the
acquired values. In the Average Mode, a Data Acquisition Directions of
rotation is defined in the same manner as it is in the Standard Mode. How-
ever, instead of always over-writing the last data reading stored at the same
angular position, is will be averaged with previous readings if the laser head
has been moved at least 20 degrees in the reverse direction or a full 360
degree sweep is performed. In this mode of operation, once the direction
of rotation is defined by the laser heads, only the data in that direction of
rotation will be acquired; therefore, any backward rotation of the shaft due
to backlash will not be acquired and thus will not affect the alignment
results. The following scenario will clarify the intended operation.
1.····Assume that the Data Acquisition Direction of rotation is defined as
clockwise (see scenario for Standard Mode).
2. ···If the laser heads are rotated in the clockwise direction to an angle of
50 degrees, data is acquired and stored for each angular position in
this rotation.
3. ···If the laser heads are then rotated in the counter-clockwise direction
for 10 degrees (back to an angle of 40 degrees), all data acquired is
ignored in the counter-clockwise direction since the direction of
rotation is not in the Data Acquisition Direction of rotation.
4. ···If the laser heads are again rotated in the clockwise direction for 25
degrees (to an angle of 65 degrees), the data acquired for each angular
position will over-write the previous data acquired because the angle
of negative rotation was not at least 20 degrees.
5. ···If the laser heads are then rotated in the counter-clockwise direction
for 30 degrees (back to an angle of 35 degrees), all data is ignored
because of the direction of rotation.
6. ···Now if the laser heads are rotated in the clockwise direction for 360
degrees. The data for the angular positions in the range 36 - 65
degrees will be averaged with the previous values since there has
been a rotation of at least 20 degrees away from the stopping point.
The data for the angular positions in the range 66 - 359 degrees will
receive a data value since the direction of rotation is correct. The data
angular positions in the range 0 - 35 degrees will be averaged with the
previous values since the rotation in the clockwise direction passed
the starting point (i.e. 360 degree sweep).