RTC
®
5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control
123
Notes
• If no correction table has been loaded into the
RTC
®
5’s memory, then the RTC
®
5 will transmit
unintended values to the scan system. If no 2D or
3D correction file for the specific optical configu-
ration is available, then at least a 1to1 (2D or 3D)
correction table should be loaded (see "1to1
Correction Tables", page 124).
Correction files should be loaded at the begin-
ning of an application program, before or after
loading the program file (via load_program_file,
page 340)
(1)
. They should absolutely be loaded
and assigned prior to first-time starting of a list or
issuance of a control command (e.g. goto_xy,
page 296) that sets the scan system’s
galvanometer scanners in motion.
• If only one of the two scan head connectors has
been assigned a 2D correction table (e.g. initial-
ization via load_program_file only assigns a
correction table to the primary scan head), then
the other scan head connector will transmit no
signals.
• As of version DLL 521, OUT 521,
load_correction_file automatically calls
select_cor_table after loading the correction
table. This results in both assignment of a
correction table and triggering of a jump with
jump_speed
(no hard jump) to the corrected
galvanometer scanner position.
– However, if load_correction_file is called prior
to loading a program file via
load_program_file, then the automatic call of
select_cor_table will have no effect
(1)
. And
though load_program_file assigns a correc-
tion table – as with
select_cor_table(1,0)
– it
won’t trigger scanner motion to the corrected
position. Therefore, immediately after the
load_program_file command, the laser focus
will initially be centered in the image field (0|0)
– even if a correction table #1 had been
previously loaded via load_correction_file. The
desired image field correction becomes active
only after a subsequent select_cor_table,
select_cor_table_list, jump or marking com-
mand.
–If load_correction_file is called after
load_program_file, then the call of
select_cor_table will execute with the default
parameter values (
HeadA
= 1,
HeadB
= 0) or – if
select_cor_table or select_cor_table_list was
called in the meantime – with the parameters
used there. If you require a different assign-
ment, then you must call select_cor_table or
select_cor_table_list (again) using the appro-
priate parameter values. As of version DLL 527,
OUT 529, the command only returns to the
application, after the select_cor_table-induced
jump to the corrected galvanometer position
has completed.
•RTC
®
5 correction files differ from those of prior
RTC
®
products (with the file extension
.ctb
) in
terms of size, structure and content. If ct5 and ctb
correction files have the same file name (except
for the different extensions), then they were
calculated for the same optical configuration. For
converting older correction files, see "Converting
Correction Files", page 125.
Notes on versions older than DLL 521, OUT 521:
• Here load_correction_file does not call
select_cor_table. Here, the command
select_cor_table or select_cor_table_list should be
called directly after loading a correction table (or after a
subsequent load_program_file command) to ensure
that the current position, in accordance with the most
recently loaded correction table, will be attained
immediately via a smooth transition (with
jump_speed
) instead of via a hard jump initiated by
the subsequent jump or marking command. If you
don’t explicitly call select_cor_table or
select_cor_table_list, then some boards might also
output unexpected initialization-related galvanometer
scanner positions.
• With such older versions, select_cor_table or
select_cor_table_list must also absolutely be called
after loading if load_correction_file is used to replace
an already loaded and assigned 2D correction table by
a 3D correction table (or a 3D table by a 2D table or by
another 3D table). Otherwise the newly loaded
correction table will not be fully effective. The same
applies when the correction table is loaded after
load_program_file (though initialization assigns a
table as via
select_cor_table(1,0
), it doesn’t
trigger scanner motion to the corrected output
position). On the other hand, calling select_cor_table
or select_cor_table_list is not obligatory, if a 2D
correction table is replaced with another 2D correction
table. But even in this case, select_cor_table or
select_cor_table_list should be called to avoid hard
jumps.
(1) load_program_file deletes correction tables number 3 and 4.
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