RTC
®
5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control
108
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One way of avoiding this problem is to generally
select a LaserOff delay that is
longer
than the
LaserOn delay (LOffD > LOnD, as with the prede-
cessor boards). On the other hand, the RTC
®
5
now checks each mark vector and – if necessary –
automatically extends the LaserOff delay for the
respective mark vector so that LaserOff occurs
only after LaserOn. Laser delays can thus be set
independently of each other. Then each mark
vector is marked for at least 0.5
µ
s.
(2)
Adjustment of the Scanner Delays
Under some circumstances with predecessor
boards, a short delay could result in laser control
errors if a non-mark command (e.g.
jump_rel( 0, 0 )
or
) comes between
two mark commands. Here, the laser would be
switched off during the second mark command,
but unexpectedly not switched on again if the
LaserOff delay is longer than the sum of the
MarkDelay (and any jump delay) and the LaserOn
delay (see
).
One way of avoiding this problem is to generally
select a mark delay that is larger than the differ-
ence between the LaserOff delay and the LaserOn
delay (markD>LOffD-LOnD, as with the prede-
cessor boards). But here, a minimum mark delay
size is required that otherwise wouldn’t be neces-
sary where mark commands directly follow
another; this thus unnecessarily increases the
total marking time. On the other hand, the RTC
®
5
now checks each mark command’s laser delays
and automatically extends the scanner delay so
that a preceding LaserOff delay first finishes
before another Laser-On follows. Thus, marking
time is only increased when necessary. The
scanner delays can now be optimized indepen-
dently of the laser delays.
The same applies for the
edgelevel
of the
variable polygon delay as well as for a too-short
polygon delay if a polygon chain is continued via
a list change but no
is used and the
second list is started immediately after the first
list finishes processing. For predecessor boards in
the latter case, the laser might remain switched-
off for the rest of the polyline.
For very large LaserOn delays extending across a
mark command as well as a subsequent non-
mark command and up to the next mark
command, appropriate scanner delays will be
inserted to prevent overlap of a not-yet-expired
LaserOn delay with the start of the second
marking command. Otherwise, the currently
executing LaserOn delay would have gotten over-
written and the laser wouldn’t have even
switched on for the first marking command, but
instead only for the second marking command
and only after expiration of the LaserOff delay
(see
).
37
Time
Mark Command
Laser
LOff Delay
LOn Delay
corrected LaserOff delay
Time
Mark Command
Laser
LOff
Delay
LOn Delay
RTC
®
5 tries
to switch off
the laser
RTC
®
5 does
not switch off
the laser
without correction
with automatic correction
Automatic adjustment of LaserOff delay
38
Laser
Other Command
(jump_rel, list_nop, ...)
Mark
Command1
LOn
Delay2
LOff Delay1
Mark
Command2
Mark
Delay1
Laser
Other Command
(jump_rel, list_nop, ...)
Laser
scanner delay
is automatically inserted
Laser does not
remain on for marking 2
without correction
with automatic correction
Mark
Command1
LOff Delay1
Mark
Command2
Mark
Delay1
LOn
Delay2
Automatic adjustment of the scanner delays for small mark
delays