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XPS-Q8 Controller
XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
Example
This is the sequence of functions that initialize and home a motion group.
GroupInitialize (MyGroup)
GroupHomeSearch (MyGroup)
...
GroupKill (MyGroup)
7.3
Referencing State
The predefined home search processes described in the previous section might not be
compatible with all motion devices or might not be always executable. For instance, if
there is a risk of collision during a standard home search process. In other situations, a
home search process might not be desirable. For example, to ensure that the stages have
not moved, the current positions are stored into memory. In this case, it is sufficient to
reinitialize the system by setting the position counters to the stored position values.
For these special situations, the XPS controller's referencing state as in alternative to
the predefined home search processes.
The Referencing state should be only used by experienced users. Incorrect use
could cause equipment damage.
The Referencing state is a parallel state to the homing state, see the state diagram on
page 81, Figure 22. To enter the referencing state, send the function
GroupReferencingStart(GroupName) while the group is in the NOT REFERENCED
state.
In the Referencing state, the function
GroupReferencingActionExecute(PositionerName, Action, Sensor, Parameter) will
perform certain actions like moves, position latches of reference signal transitions, or
position resets. The function
PositionerSGammaParametersSet(PositionerName) can be used to change the
velocity, acceleration and jerk time parameters.
To leave the referencing state, send the function
GroupReferencingStop(GroupName). The Group will then be in the HOMED state,
state number 11.
The syntax and function of the function
GroupReferencingActionExecute(PositionerName, Action, Sensor, Parameter) will
be discussed in detail. With this function, there are four parameters to specify:
• PositionerName is the name of the positioner on which this function is executed.
• Action is the type of action that is executed. There are eight actions that can be
distinguished into three categories: Moves that stop on a sensor event, moves of
certain displacement, and position counter reset categories.
• Sensor is the sensor used for those actions that stop on a sensor event. It can be
MechanicalZero, MinusEndOfRun, or None.
• Parameter is either a position or velocity value and provides further input to the
function.
NOTE
78
Motion Tutorial
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