Output Synchronization - Scanlab RTC 5 PC Interface Board Installation And Operation Manual

7.4.10 Output Synchronization

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The RTC 5 provides the so-called (galvanometer)
"output synchronization" functionality for synchro-
nizing the scan system's scanning motions (during all
marking commands) to the laser pulses of a free-
running laser.
The laser pulse signal (the synchronization master
clock) must be supplied at the LASER connector's
DIGITAL IN1 digital input. You can enable or disable
output synchronization via bit#6 of
set_laser_control.
When enabled, output synchronization affects all
marking commands (mark, arc and ellipse). At each
marking command's start, the RTC
time shift between that marking command's starting
time and the first laser pulse after LaserOn
appropriately corrects the scan system's output
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values. The RTC 5 thus ensures that the galva-
nometer scanner's position upon the first laser pulse
output after LaserOn won't depend on random phase
shifts of the laser pulse. This way, jittery line images
can be avoided (see figure
without output synchronization:
statistical variation of
line starts due to lack
of synchronization
between laser pulses
and scan motion
with enabled output synchronization:
clean line starts
Example of line image marked with a free-running laser
(1) the first laser pulse output following the LaserOn delay
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RTC 5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control
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5 determines the
(1)
and
54).
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Notes (as of version RBF 527):
• The supplied laser pulse signal must have a
frequency between 50 kHz and 6.4 MHz and its
pulse length must exceed 0.080 µs.
• The output period of the laser control signals
must be set according to the laser pulse
frequency in the user application (before
enabling output synchronization) via
set_laser_pulses, set_laser_pulses_ctrl
set_laser_timing.
• For frequencies between 50 kHz and 100 kHz, the
LaserOn delay must be set to 50 µs, otherwise the
LaserOn delay must exceed 40 µs.
• If no laser pulse appears at the DIGITAL IN1 digital
input within 20 µs of a marking command's start,
then no output synchronization will be
performed on that command's output.
• Output synchronization can also be used in
conjunction with Sky-Writing.
• Output synchronization can't be used together
with pixel mode.
or
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