4.2.3. Predefined displacement mode¶
The predefined displacement mode provides displacement of the stage for predefined value relative to zero position (if this is a first command since the controller started) or relative to position reached by the motor after the previous commands are completed, i.e., the destination point coordinate is a relative value. This mode is useful when the absolute position is unknown or doesn’t matter.
The predefined displacement mode is exactly analogous to Rotation for predefined point mode. The differences concern the destination position computing rules only. While there is no motion actually, calling the predefined displacement command rotates the motor relatively to current position. If this command is sent during the rotation to the position (MOVE, MOVR, SSTP, STOP, LOFT), then the displacement interval adds to destination position and the controller re-adjusts for the new destination point while the motor is rotating. If this command comes during the rotation for certain direction, then the displacement value adds to previous destination position and the motion automatically re-adjusts for the new position.
The displacement is always performed relative to position reached by stage while performing one of the previous command, MOVE, MOVR, SSTP, STOP, LOFT, or while performing the displacement after the previous incoming synchronization pulse has been received, despite whether the motion has been completed or interrupted.
The predefined displacement mode is activated either by corresponding command or by incoming synchronization pulse. For more information please refer to TTL synchronization chapter.