RTC
®
5 PC Interface Board
Rev. 1.9 e
8 Advanced Functions for Scan Head and Laser Control
187
innovators for industry
8.7.6 Virtual Image Field
When using the virtual 24-bit image field’s extended
range (see
) for Processing-on-the-fly appli-
cations, you can also load command lists with objects
up to 16 times larger than the real 20-bit image field.
These command lists will get fully and autonomously
processed without the need for additional control
measures.
In 1D Processing-on-the-fly applications (e.g. work-
pieces on a conveyor belt), objects can only exceed
the real image field in one dimension (parallel to the
Processing-on-the-fly direction). In 2D Processing-on-
the-fly applications (e.g. with an XY translation
stage), the command list’s markable objects can be
distributed across the entire virtual image field.
If your overall marking job consists of multiple
marking sub-jobs (“tiles“) whose extents don’t
exceed the real image field, then you can also use
Processing-on-the-fly functionality to merely move
each sub-job into the real image field for subsequent
processing (here, sub-job processing even may occur
without Processing-on-the-fly motions). But if the
overall marking job
isn’t
decomposable into separate
tiles (e.g. when marking a large closed frame around
other objects), then continuous Processing-on-the-fly
marking will be necessary.
The possibility of marking objects outside the real
image field exists only because of the following:
When a list is processed with activated Processing-
on-the-fly correction, then coordinate values outside
the real image field get clipped to the boundaries of
the real image field (20 bits) only after Processing-on-
the-fly correction (see
). If the
supplied coordinate values take into account the
motion of the workpiece or scan system as well as the
defined Processing-on-the-fly correction and any
defined track delay (see
),
then coordinate values outside the real image will be
transformed at runtime into coordinate values within
the real image field. Coordinate values residing
outside the real image even
after
Processing-on-the-
fly correction will still be clipped to the boundaries of
the real image field (here, the
error bits get set automatically, see
To ensure that coordinate values never lie outside the
20-bit image field
after
Processing-on-the-fly
correction, always structure your command lists so
that – during list execution – exceedance of the 20-
bit image field will always be preceded (and thereby
avoided) via an appropriate motion of the conveyor
belt, XY stage etc. For this purpose, you must insert
or
into the list. These commands interrupt list execution
until specific encoder or McBSP values are achieved
(also see
responsible for appropriate decomposition of the
overall marking task and synchronization with 1D or
2D Processing-on-the-fly motion (of a conveyor belt,
XY translation stage, etc.).
applications, coordinate transforma-
tions in the entire virtual image field are also possible
(see the
section "Coordinate Transformations in the
