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XPS-Q8 Controller
To illustrate this, let's consider a typical scanning application. If there is an error on the
stepping axis of the XY table (which is set-up as an XY group), only the XY table is
disabled while the auto-focusing tool (a vertical stage that is defined as a separate
SingleAxis group) continues to function.
Each of the five available motion groups has specific features:
6.3.1
Specific SingleAxis Group Features
Master-Slave – To enable this function, the slaved positioner must be defined as a
SingleAxis group. The master positioner can be a member of any motion group. So it is
possible to define a Positioner as a slave of another positioner that is part of an XYZ
group.
6.3.2
Specific Spindle Group Features
The Spindle Group is a single positioner group that enables continuous rotations with no
limits and with a periodic position reset.
Master-Slave - In Master-Slave spindle mode the master and the slave group must be
Spindle groups.
6.3.3
Specific XY Group Features
Line-Arc trajectories, XY mapping – These features are only available with XY groups.
It is not possible for an XY group to perform a Spline or a PVT trajectory. Also, an XY
group cannot be slaved to another group, however, any positioner of an XY group can
be a master to a slaved SingleAxis group.
6.3.4
Specific XYZ Group Features
Spline trajectories, XYZ mapping – These features are only available with XYZ groups.
It is not possible for an XYZ group to perform a Line-Arc or a PVT trajectory. Also, an
XYZ group cannot be slaved to another group, however, any positioner of an XYZ
group can be a master to a slaved SingleAxis group.
6.3.5
Specific MultipleAxes Features
PVT trajectories – PVT trajectories are only available with MultipleAxes groups. It is
not possible for a MutipleAxes group to perform a Line-Arc or a Spline trajectory. Also,
a MultipleAxes group cannot be slaved to another group. However, any positioner of a
MultipleAxes group can be a master to a slaved SingleAxis group.
6.4
Native Units
The XPS controller supports user-defined native units like µm, inches, degrees or
arcsecs. The units for each positioner are set in the configuration file where the
parameter EncoderResolution indicates the number of units per encoder count. When
using the XPS controller with Newport stages, this part of the configuration is done
automatically. Once defined, all motions, speeds and accelerations can be commanded
in the same native unit without any math needed. All other parameters like stage travel,
maximum speed and all compensations are defined on the same scale as well. This is a
great advantage compared to other controllers that can be commanded only in multiples
of encoder counts, which can be an odd number.
In the XPS controller there are 4 types of position information for each positioner:
TargetPosition, SetpointPosition, FollowingError and CurrentPosition. These are
described as follows:
The CurrentPosition is the current physical position of the positioner. It is equal to the
encoder position after all compensations (backlash, linear error and mapping) have been
taken into account.
The SetpointPosition is the theoretical position commanded to the servo loop. It is the
position where the positioner should be, during and after the end of the move.
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XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
Motion Tutorial
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