RTC
®
5 PC Interface Board
Rev. 1.9 e
8 Advanced Functions for Scan Head and Laser Control
172
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8.6.3 3D Marking Commands
The RTC
®
5’s command set includes the following 3D
vector and timed 3D vector commands:
•
•
,
•
•
•
In addition the RTC
®
5 command set provides the
following 3D arc commands which allow spiral
marking:
•
Except for the additional motion in the third
dimension, these commands function identically to
the corresponding 2D marking commands:
• The specified vectors or arcs will be microvec-
torized (with the same output period as with 2D
commands, see
• As with 2D commands, jump and marking speeds
can be specified via
and
). As for timed 2D
vector commands, for timed 3D vector
commands, the speeds will be automatically
determined based on the specified jump or
marking duration.
• 3D image field correction will be applied in accor-
dance with the 3D correction table assigned via
(see
• For jump and mark commands, the laser control
signals will be switched on and off while taking
delay settings into account (see
The RTC
®
5 simultaneously calculates output values
for the galvanometer scanners of the scan system and
the corresponding focal lengths (or focal intercepts)
and output values for the Z-axis. Here, the RTC
®
5 uses
appropriate data from the assigned 3D correction
table. SCANLAB individually calculates each
correction table based on the optical configuration of
the specific 3-axis system and all available optical
system data (such as mirror geometry, calibration,
objective specifications and Z-axis optics specifica-
tions). Each correction table is stored in a correction
file named (
*.CT5
) in the RTC
®
5 software package
(also see
).
In RTC
®
5 mode, the X and Y vector coordinates of a
vector must be specified as signed 20-bit numbers
(i.e. as numbers between – 524288 and +524287),
however the Z coordinates in a 3D system must be
signed 16-bit numbers (i.e. numbers between
– 32768 and +32767). Therefore, the calibration
factor (the ratio of a point coordinate in
bits
and the
actual position of the point in
millimeters
) is 16 times
smaller in the Z direction than in the X and Y direc-
tions:
K
z
=
K
xy
/ 16.
In contrast, the following should be used for RTC
®
4
compatibility mode (as with the RTC
®
4):
K
x
=
K
y
=
K
z
=
K
xy
/ 16.
The RTC
®
5 (in RTC
®
5 mode as well as in RTC
®
4
compatibility mode) automatically upscales Z coor-
dinate values internally to 20-bit values, so that the
three dimensions of space can be handled equiva-
lently in terms of jump or marking speed values.
Notes
• If vector-defined laser control is activated via
, then para-mark and para-
jump commands (
,
,
) can also be used.
These commands simultaneously vary a signal
parameter linearly along the mark or jump vector
(see
Ctrl
= 7), for example, the
focus shift (i.e. an offset to the calculated focal
length) will vary (as with
or
).
• The size of the usable image field and the
maximum focus shift in the Z direction (height of
the usable working volume) can be obtained
from the “Readme.txt” file supplied with the 3D
correction file or from the user manual of the
3-axis scan system or the vario
SCAN
(“Technical
Specifications” chapter).
• If a Z axis serves the purpose of maintaining the
laser focus in a particular plane, then 2D vector
commands can be used, too (after the desired Z
position was set via a 3D vector command). 2D
vector commands have no effect on the Z
position, but regulate the focal length – if the 3D
option is enabled and a 3D correction table was
assigned – so that the laser beam maintains
focused in the same plane.