Table of Contents
Advertisement
XPS-Q8 Controller
10.0
Compensation
The XPS controller features different compensation methods that improve the
performance of a motion system:
Backlash compensation: The use of backlash compensation improves the bi-
directional repeatability and accuracy of a motion device that has mechanical play.
Backlash compensation is applicable to all positioners, but it is not available in all
motion modes. When backlash compensation is activated, the XPS controller adds a
user-defined BacklashValue to the TargetPosition to calculate a new target position
whenever the direction of motion reverses. This internally used new target position is
then the basis for the calculations of the motion profiler. No modification of the actual
target is performed.
Linear error compensation: The linear error compensation helps improve the
accuracy of a motion device by eliminating linear error sources. Linear errors can be
caused by screw pitch errors, linear increasing angular deviations (abbe errors), thermal
effects or cosine errors (misalignment between the feedback device and the direction of
motion). Linear error compensation is applicable to all positioners. Its value is defined
in the stages.ini. When set to other than zero, the encoder positions are compensated by
this value. Linear error compensation can be used in conjunction with other
compensation. For this reason, keep in mind the effects of using linear error
compensation in addition to other compensation methods.
Positioner mapping: In contrast to the linear error compensation, positioner mapping
also allows compensation for nonlinear error sources. Positioner mapping is done by
sending a compensation table to the XPS controller and configuring the needed settings
in the stages.ini. Positioner mapping is available with all positioners and works in
parallel with other compensations except for the backlash compensation method. Better
accuracy performance is achievable with linear compensation and positioner mapping
combined.
XY mapping: XY mapping is only available with XY groups. It allows compensation
for all errors of an XY group at any position of the XY group by sending two
compensation tables to the XPS controller (x and y compensations mapped to x and y
positions). The XY mapping is dynamically taken into account on the corrector loop of
the XPS controller. XY mapping works in parallel to other compensation methods.
Keep in mind that the results of XY mapping may not be the same as those of Positioner
mapping or linear compensation alone.
XYZ mapping: XYZ mapping is only available with XYZ groups. It compensates for
all errors of an XYZ group at any position of the XYZ group by sending three
compensation files to the XPS controller (x compensations mapped to x, y, and z
positions, and so on). The XYZ mapping is dynamically taken into account on the
corrector loop of the XPS controller. XYZ mapping works in parallel to other
compensation methods. Keep in mind that the results of XYZ mapping may not be the
same as those of Positioner mapping or linear compensation alone.
TargetPosition, SetpointPosition & CurrentPosition are accessible via function and
Gathering (Data Collection).
SetpointVelocity, SetpointAcceleration & FollowingError are accessible via
Gathering (Data Collection).
111
XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
Motion Tutorial
Advertisement
Table of Contents
