Pvt Trajectory Verification And Execution - Newport XPS-Q8 Users Manual, Software Tools And Tutorial

XPS-Q8 Controller
XPSDocumentation V1.4.x (EDH0301En1060 — 10/17)
Figure 34: Executing the trajectory data file with the PVT algorithm.
8.3.8

PVT Trajectory Verification and Execution

Here are four functions to verify or execute a PVT trajectory:
• MultipleAxesPVTVerification(): Verifies a PVT trajectory data file.
• MultipleAxesPVTVerificationResultGet(): Returns the results of the last
trajectory verification call, actuator by actuator. This function works only after a
MultipleAxesPVTVerification().
• MultipleAxesPVTExecution(): Executes a PVT trajectory.
• MultipleAxesPVTParametersGet(): Returns the trajectory's current execution
parameters. This function works only while executing a trajectory.
The function MultipleAxesPVTVerification() can be executed at any moment and is
independent of the trajectory execution. This function does the following:
• Checks the trajectory file for data and syntax coherence.
• Simulates the trajectory to determine the positioner's travel requirements in negative
and positive directions and the maximum allowed speed and acceleration for each
positioner. This function determines whether the trajectory is executable.
• If all is OK, it returns an "OK" (0). Otherwise it returns a corresponding error. An
error for instance is reported if one of the positioner's speed or acceleration reached
during the trajectory exceeds the maximum allowed speed or acceleration.
The function MultipleAxesPVTVerificationResultGet() can be executed only after a
MultipleAxesPVTVerification(). It returns the trajectory limits for each positioner,
which are the travel requirements in positive and negative directions, the achieved
maximum speed and acceleration.
To execute a PVT trajectory, send the function MultipleAxesPVTExecution() while
specifying the file name and the number of cycles. This function does not verify the
trajectory's coherence or geometric conditions (exceeding any positioner's min. or max.
travel, speed or acceleration) before execution, so users must be careful when executing
a trajectory without verifying the trajectory first. In case of an error during execution,
because of bad data or because of a following error, the motion group will make an
emergency stop and will go to the disabled state.
Finally, the function MultipleAxesPVTParametersGet() returns the trajectory name and
the number of the trajectory element that is currently being executed. This function
returns an error if the trajectory is not executing.
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