Positionerpositioncomparepulseparametersset - Newport XPS Programmer's Manual

XPS Unified
EDH0373En1023 — 01/18
7.2.1.277

PositionerPositionComparePulseParametersSet

Name
PositionerPositionComparePulseParametersSet – Sets the position compare PCO
pulse parameters.
Input tests
- Refer to section 7.1: "Input Tests Common to all XPS Functions".
- Checks the positioner type (must not be a secondary positioner): (-8)
- Checks input parameter values: (-17)
• PCOPulseWidth value must equal to 0.2 (default), 1, 2.5 or 10 (µs)
• EncoderSettlingTime value must equal to 0.075 (default), 1, 4 or 12 (µs)
- Checks position compare state (must be disabled): (-22)
- Checks the position encoder ("AquadB" or "AnalogInterpolated"): (-24)
- Checks if the CIE board supports this function: (-115)
Description
This function sets two additional parameters for the position compare output trigger of
the PCO connector on the XPS controller cards. The first additional parameter is the
pulse width. The second parameter is the encoder settling time value, which is the time
the encoder inputs have to stabilize after a change of state is detected.
These parameters are used only when using the position compare mode. For a more
thorough description of the position compare output, please refer to the XPS Motion
Tutorial section Triggers/Position Compare Output.
When changing the PCO Pulse settle time you must limit the maximum velocity of
the stage accordingly, otherwise you will loose the PCO position and generate the
wrong number of pulses at wrong positions.
For example, if you set the EncoderSettlingTime to 4 µs, the maximum PCO
encoder frequency need to be limited to less than 0.25 / 4e
So, if EncoderScalePitch = 0.004 mm and HardInterpolatorFactor = 200 then the
stage maximum velocity must ≤62.5e
PCO will not work properly.
How to determine PCO encoder frequency:
1. For AquadB encoder:
PCO encoder frequency = Velocity / EncoderResolution
2. For analog interpolated encoder:
PCO encoder frequency = Velocity * HardInterpolatorFactor / EncoderScalePitch
Example: XML310 stage (EncoderScalePitch = 0.004 mm,
HardInterpolatorFactor = 200). If Velocity = 10mm/s = >PCO encoder frequency = 10
* 200/0.004 = 500 kHz
NOTE
3 * 0.004 / 200 = 1.25 mm/s, otherwise the
416
Programmer's Manual
-6 = 62.5 kHz.