THORLABS LNR502E, User Manual

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LNR502E Encoded Long Travel, Linear Stage with Stepper Motor Actuator
Encoder Position Setpoint Window (counts)
- When an encoded move is corrected, the system attempts to 'reach' a required
position setpoint (i.e. encoder count). This parameter specifies a window of acceptability (in encoder counts) that the system
must achieve.
For example, when set to a value of 1, the system must get to within 1 encoder count either side of the required position. This
setting is useful for noisy systems (i.e. mechanical noise causing jitter on the encoder count) where achieving a precise
encoder count may prove difficult.
For an encoder calibration factor of 10000/mm, a value of 1 for this setting means the system will position to -0.1micron
of the required position.
Single Microstepping Window - Specifies a window within which the system attempts to reach the required position setpoint
by single microstep stepping - a very accurate stepping mode. For example, if this parameter is set to a value of 10, and if the
encoded move initially ends up within 10 counts (1 micron for a calibration factor of 10000) either side of the required position,
the system will single microstep to reach the required position.
If at the end of the initial encoded move, the system detects the encoder position is outside of this window, then the system
steps at whatever multiple of microsteps is specified by the 'Correction Move Distance' parameter described below, until the
encoder position falls within the Single Microstepping Window and single microstepping can take place.
Stop Short Distance
- When the 'Position (Stop Short & Correct)’ position correction mode is enabled (described in the Encoder
Operation section), this parameter specifies the distance (in microsteps) to stop short of an encoded move.
Assuming 409600 microsteps per revolution of the stepper motor and a 1mm pitch lead screw, a value of 4100 equates to
approximately 10 microns stop short distance.
Correction Move Distance
- Specifies the size of correction step (in microsteps) to use when the system issues correction
moves outside of the distance set in the ‘Single Microstepping Window’ parameter described above.
Assuming 409600 microsteps per revolution of the stepper motor and a 1mm pitch lead screw, a value of 80 equates to
approximately 0.2 micron step size.
Note
These settings are set to suitable defaults automatically when an encoded stage
type has been associated with the motor channel (using the APT Config utility).