Scanlab RTC6 PCIe Board - Page 165

RTC6 boards
Doc. Rev. 1.0.21 en-US
7 Basic Functions for Scan Head Control and Laser Control
165
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Notes
• By set_sky_writing and
set_sky_writing_mode_list, you can switch back
and forth between Sky Writing Mode 1 and
Sky Writing Mode 2 or Sky Writing Mode 3.
Temporarily switching off is also possible, as long
as Timelag > 0.
• When searching for appropriate Sky Writing
parameters, initially set_sky_writing and
Sky Writing Mode 1 should be used: as start
value for the Timelag parameter, the
Tracking Error of the galvanometer scanners.
should be set. Then Timelag (with
LaserOnShift = 0) can be fine-tuned such that
marking vector ends are exactly marked and only
afterwards the parameter LaserOnShift should be
adjusted (keeping constant the parameter
Timelag ), so that the marking vectors’ beginnings
are exactly marked, too.
In a second step set_sky_writing_para can be
used to optimize the parameters Nprev and Npost :
Nprev and Npost may be decreased (relating to the
default settings of set_sky_writing, see below)
to minimize marking times. Alternatively, Nprev
may be increased to enable a correspondingly
large negative LaserOnShift .
• With set_sky_writing and set_sky_writing_list,
Nprev and Npost are predefined:
– Nprev = approx. 0.15 × Timelag
– Npost = approx. 0.1 × Timelag
This results in the following run-in and run-out
durations:
• With set_sky_writing_para or
set_sky_writing_para_list, you can also specify
other run-in and run-out phases, for example,
shorter ones to reduce marking times (but this
may be at the expense of accuracy).
Shorter run-in and run-out phases are particularly
beneficial when lines are marked in only one
direction without interruption and jump speed
and mark speed are set equally.
Note that in Sky Writing mode no automatic
adjustment of laser and Scanner Delays is
performed:
– If the next Mark Command’s run-in phase
begins when the preceding Mark Command’s
LaserOn Delay has not yet expired, then the
laser does not switch on for the preceding
command.
– If the next Mark Command’s run-out phase
begins when the preceding Mark Command’s
LaserOff Delay has not yet expired, then the
laser does not switch off for the preceding
command.
– In Sky Writing Mode 1, a positive LaserOnShift
time (in µs) should exceed the smallest
occurring marking time by no more than
(20 × Npost – Timelag ) – and in
Sky Writing Mode 2 and Sky Writing Mode 3
by no more than (10 × Npost – Timelag ).
Otherwise, the laser is not switched on for this
marking.
Mode Duration [ Timelag ]
Run-in 1 3
Run-in 2, 3 1.5
Run-out 1 2
Run-out
2, 3 1