Rev K Jan 2020
Page 12
Chapter 3 Mechanical Installation
3.4 Calibration of Motor Drives
Calibration enables the server to correct for any mechanical errors inherent in the
system. Mechanical components, such as the leadscrew and linkages, can be
machined only within a certain tolerance, e.g. the leadscrew may be nominally 1mm
but actually 1.0005mm, giving a 0.5 micron error. In practice, these errors accumulate
from a number of sources, however they are repeatable and therefore, can be
compensated.
During calibration, the total positional error is measured at a large number of points
and these errors are stored as a look up table (LUT). The LUT is saved as a
calibration file, one file for each particular stage. The file is then linked to the
appropriate stage using the APT Config utility. Whenever the stage is moved, the LUT
is consulted to ascertain the precise movement required to achieve the demanded
position.
The use of a calibration file is optional. Without it, the repeatability and resolution of
the stage are unaffected, but no compensations are made to enhance the accuracy
Calibration files can be downloaded from the support documents section on the
product web page, one file for each serial number. Details on assigning a calibration
file are contained in the
APTConfig On Line Helpfile.
3.5 Mounting Equipment and Devices
3.6 Transportation
Caution
Ensure that any devices and components attached to the moving platform are
securely fastened. Incorrectly attached components could come loose when
the stage is operated.
Caution
When attaching accessories, e.g. fiber holders, to the top platform do not use
long bolts that protrude into the unit as this could damage the internal
mechanism. The fixing thread should be no longer than 6 mm (0.24”).
Caution
When packing the unit for shipping, use the original packing. If this is not
available, use a strong box and surround the unit with at least 100 mm of shock
absorbent material.
