Scanlab RTC 5 PC Interface Board Installation And Operation Manual page 108

without correction
LOn Delay
LOff
Delay
Mark Command
®
RTC
to switch off
the laser
with automatic correction
LOn Delay
LOff Delay
Mark Command
corrected LaserOff delay
Automatic adjustment of LaserOff delay
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
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 µs.
(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 list_nop) 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 figure 38).
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
now checks each mark command's laser delays
®
RTC 5 PC Interface Board
Rev. 1.9 e
7 Basic Functions for Scan Head and Laser Control
Laser
Time
®
5 tries RTC 5 does
not switch off
the laser
Laser
Time
37
®
5
®
5
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.
without correction
LOff Delay1
Laser
Mark
Delay1
Mark
Command1
Other Command
(jump_rel, list_nop, ...)
remain on for marking 2
with automatic correction
LOff Delay1
Laser
Mark
Delay1
Mark
Command1
Other Command
(jump_rel, list_nop, ...)
is automatically inserted
Automatic adjustment of the scanner delays for small mark
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 auto_change (see page 238)
or start_loop (see page 512)
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 figure 39 on page 109).
LOn
Delay2
Mark
Command2
Laser does not
Laser
LOn
Delay2
Mark
Command2
scanner delay
38
is used and the
108