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finterlaced

Description

finterlaced is a 1-motor continuous scan, like fscan, executed in 2 passes. In the first pass, only one acquisition is performed every second point; second pass, the remaning acquisitions are performed. The objective is to cover the entire scan distance without gaps, during readout phase as it exist in fscan. Consequently, lima detectors are used in EXTERNAL_GATE mode and triggers are always in POSITION. This ensures that the start of the second phase exposures match exactly the end of first phase exposures.

finterlaced supports 3 specific modes based on the mode parameter. Due to the acquisition schema, images are not taken in natural order, which imposes care, when processing the images. The following diagrams show the frame orders (acq number) and motor movements for the 3 modes.

  • REWIND: motor is rewound to the start position after 1st pass finterlaced rewind_schema
  • ZIGZAG: motor perform the second pass in opposite direction. This avoids rewinding the motor to the start position and saves time. finterlaced_zigzag_schema
  • FORWARD: only supported on rotation motors (i.e. motors which can rotate indefinitely). The motor is not stopped after the first pass and continues its rotation to perform the second pass in one movement. This saves a lot of travel time, when performing acquisitions on a 360 degree basis. finterlaced_forward_schema

Common parameters implemented: save_flag, display_flag, sync_encoder, home_rotation, acc_margin, sampling_time

Parameters

parameter description
motor bliss motor object (not motor name string !!)
start_pos start position of first acquisition
acq_size size of one acquisition in position
acq_time [sec] acquisition time
npoints total number of points
mode REWIND,ZIGZAG,FORWARD interlaced mode as described above.
shift_pos default=0.0 position shift of start position of second interlaced pass.

Common parameters implemented: save_flag, display_flag, sync_encoder, home_rotation, acc_margin, sampling_time.