RTC
®
4 PC Interface Board
Rev. 1.3 e
4 Principle Of Operation
16
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The length
∆
s of each microstep is
∆
s =
v
·
∆
t,
where
v
is the current jump speed (marking speed).
The output period
∆
t of the position update is usually
fixed at 10
µ
s. It is the same for 2D and for 3D appli-
cations. The output period cannot be set by the user.
The 16-bit data output width of the RTC
®
4 allows up to 2
16
microsteps per vector or arc. If the marking speed is quite
low and the vector or arc is very long, a step period of 10
µ
s
would possibly lead to more than 2
16
microsteps. In this
case, the
RTC
®
4
automatically increases the output period to
20
µ
s (or to a suitable multiple of 10
µ
s, if necessary).
Marking Time
The marking time consumed by any particular
marking process can be measured by calling the
command
before and after the marking process. This command
saves the current value of the RTC
®
4’s integrated
timer and resets the timer value to 0. The measured
time can be read via the command
, which returns the timer value saved during
the most recent call of
4.3 Delays
The timing of the scan head and laser control signals
must be compatible with the dynamic behavior of the
scan system, i.e. the response of the scanners and the
laser, and the specific interaction between the work-
piece and laser radiation.
To accomplish this, the user can set the following
delays
:
• Laser On delay
• Laser Off delay
• Jump delay (optional variable)
• Mark delay
• Polygon delay (optional variable)
All delays are described in detail in this chapter.
Laser Delays
The LaserOn delay and the LaserOff delay are set by
the list command
.
The time resolution for the laser delays is
1
µ
s
.
The delays must be appropriate for the defined jump
speed and marking speed (also see
• There are two different laser delays:
LaserOn delay
and
LaserOff delay
.
• The laser delays affect when the laser is turned
on or off before or after a mark or arc command
or a series of mark and arc commands. Laser
delays do
not
affect the total marking time,
except when they are negative.