RTC6 boards
Doc. Rev. 1.0.21 en-US
7 Basic Functions for Scan Head Control and Laser Control
160
7.2.4 Sky Writing
For applications with elevated accuracy requirements
the so-called Sky Writing can be switched on. Then,
every mark vector is precisely executed at a constant
mark speed over the entire vector length.
For Mark Commands with Sky Writing enabled, the
RTC6 PCIe Board automatically performs
non-marking Sky Writing scan motions before and
after the to-be-executed vectors and arcs, see
Figure 44.
The following are always executed without
Sky Writing:
• micro_vector[*] Commands
• [*]para[*] Commands
By the Sky Writing command parameters you can
specify:
• the duration of these run-in motions
• the duration of these run-out motions
• the synchronization between scan motion and
laser control
Sky Writing is available in the following modes:
• Sky Writing Mode 1, page 160
• Sky Writing Mode 2, page 161
• Sky Writing Mode 3, page 162
Sky Writing Mode 1
In Sky Writing Mode 1, the RTC6 PCIe Board
performs the following Sky Writing motions for each
Mark Command – regardless of previous or
subsequent commands:
• In the run-in phase, the vector/arc is preceded by
a “forerun” movement performed by the
galvanometer scanners at mark speed, see
Figure 44: the galvanometer scanners are driven
a short distance parallel to the vector (or along
the arc extension), initially from the startpoint in
the opposing direction, then back to the
startpoint.
• After the vector/arc has been processed at
mark speed, it is gets a short deceleration and
retrace movement of the galvanometer scanners
(at mark speed) appended in the run-out phase.
Sky Writing Mode 1 can be switched on/off by:
• set_sky_writing
• set_sky_writing_list
• set_sky_writing_para
• set_sky_writing_para_list
44
Sky Writing motions (grey). For Sky Writing Mode 3 see
also Figure 45.
j
j
j
j
mm
m
m
mm
m
m
m
m
m
m
Jump
Arc
Jump
Mark
Mark
Jump
Jump
Arc
Jump
Mark
Mark
Jump
Sky Writing Mode 2 & 3Sky Writing Mode 1
Legend
m With mark speed.
j With jump speed.