Compensating 2D Motions; Encoder Compensation For Xy Positioning Stages - Scanlab RTC6 PCIe Board Installation And Operation Manual

8.6.4 Compensating 2D Motions

You can use the set_fly_2d
encoder-based 2D Processing-on-the-fly correction
(for example, for a xy positioning stage), particularly
for continuous marking in the virtual
Compared to an activation by
set_fly_y, this has the following advantages:
set_fly_2d
• simultaneously resets both encoders
(whereas the separate commands
set_fly_y do so with a slight temporal offset
between both channels)
• set_fly_2d allows compensation of non-linear
relations between encoder values and actual
xy positioning stage motions, see
Encoder Compensation for
xy Positioning Stages", page 249
• Even during an interruption of a
marking by wait_for_encoder_mode
wait_for_encoder_in_range, the
galvanometer scanner positions receive
continuous Processing-on-the-fly correction in
accordance with the current xy positioning stage
encoder values (whereby the laser focus remains
stationary relative to the xy positioning stage).
Thus, unnecessary jumps are avoided after
xy positioning stage forwarding motions, see
Chapter 8.6.6 "Virtual Image Field with
Processing-on-the-fly", page 252
Notes
set_fly_2d
• A correction cannot be combined with
other Processing-on-the-fly corrections, see
Section "Overview", page
• Coordinate transformations within the virtual
Image Field, see Section "Coordinate
Transformations in the Virtual Image Field",
page 169 can be activated when starting a
Processing-on-the-fly Session
values, if they have been loaded before with the
corresponding control commands.
RTC6 boards
Doc. Rev. 1.0.21 en-US
8 Advanced Functions for Scan Head Control and Laser Control
command to activate
Image Field.
set_fly_x and
set_fly_x and
Section "2D
set_fly_2d
or
242.
with changed
2D Encoder Compensation for
xy Positioning Stages
For particularly demanding marking requirements, it
might be necessary to also compensate mechanical
deviations of a xy positioning stage.
For this purpose, load_fly_2d_table
load up to two 2D compensation tables, see
page 250, onto the RTC6 PCIe Board.
Then – during a Processing-on-the-fly application
initiated by set_fly_2d – encoder values are
2D interpolated and compensated just like with field
correction tables.
To avoid unnecessary initialization motions, you can
use init_fly_2d to define a desired positioning stage
start position as the reference value for 2D encoder
compensation (and to store it on the
RTC6 PCIe Board) and to select simultaneously one of
the both correction tables.
Upon every subsequent encoder reset by set_fly_2d,
the current position is automatically applied as the
new reference position, so that the relation between
current encoder values and the absolute position of
the positioning stage is retained for compensation.
This relation remains even upon termination with
fly_return or upon a new start with set_fly_2d.
This relation does not remain, if you meanwhile
activate other Processing-on-the-fly corrections or
reset the encoders by an external /START (see
Bit #9
set_control_mode (
At any time, you can query the currently valid
reference values by get_fly_2d_offset.
Encoder compensation is applied exclusively to
Processing-on-the-fly correction. The original
uncompensated encoder values use:
• get_encoder
store_encoder
•
read_encoder
•
wait_for_encoder
•
wait_for_encoder_mode
•
wait_for_encoder_in_range
•
set_trigger
• Recording by
(Signal1/Signal2 = 43 or 44)
• Recording by get_value
can be used to
= 1 ).
249