RTC
®
5 PC Interface Board
Rev. 1.9 e
8 Advanced Functions for Scan Head and Laser Control
193
Notes
•The commands set_pixel_line,
set_pixel_line_3d, set_pixel and set_n_pixel are
list commands, i.e. they are written into a list.
• The number of pixels in an image line is limited
only by the capacity of the RTC
®
5 list buffer (see
page 570). It is suggested – especially for large
bitmaps – to set up a new list for each image line
to avoid a list change during the execution of one
line.
• Each image line must start with a set_pixel_line
or set_pixel_line_3d command.
•The pixel distance (
dX
,
dY
) in the X and
Y directions (in bits) (and with set_pixel_line_3d
also
dZ
) can be specified with floating point
numbers. This allows scaling and rotating the
image without rounding errors.
• The (half) pixel output period can be any integer-
multiple of 1/64 µs (but at least 104/64 µs) and is
independent from the 10 µs output period of the
galvanometer scanners’ microvectorized motion.
Very low pixel frequencies result in multiple
scanner steps per pixel, higher frequencies can
result in multiple pixel pulses or voltage level
changes per scanner step.
• You can implement a pixel output mode in a
10 µs raster with variable speed and/or curvilinear
paths with the help of microvector commands
(see page 197).
8.8.3 Laser Control
Depending on the type of laser employed, the laser
energy discharged at each pixel position can be
varied via the laser pulse length or the laser power per
pixel:
Variation Of Laser Pulse Length
The command set_pixel defines – for each pixel – the
length of the pixel pulse (in units of 1/64 µs), which
is outputted at the LASER1 port (for synchronization
see "Timing", page 194). The command set_n_pixel
defines the pixel pulse length for
n
directly successive
pixels of an image line.
Variation Of Laser Power
The command set_pixel allows specification of a
12-bit analog voltage level for each pixel. The value is
transferred either to the ANALOG OUT1 port or to the
ANALOG OUT2 port of the RTC
®
5 (see above, for
synchronization see "Timing", page 194). The
command set_n_pixel defines the analog voltage
level for
n
directly successive pixels of an image line.
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