Monitoring The Positioning - Scanlab RTC6 PCIe Board Installation And Operation Manual

8.1.3 Monitoring the Positioning

For some applications, it is important to monitor and,
if necessary, to document the scan system
positioning even during operation.
For this purpose, the actual position of the scan axes
must be set to be returned from the scan system by
control_command. The returned actual position
values can be queried then by
by set_trigger/set_trigger4/set_trigger8
If the returned actual positions of the scan axes are to
be compared with the Cartesian target coordinate
values (X, Y, Z), then these must be transformed back
by the corrections made on the RTC6 PCIe Board,
Chapter 7.3.6 "Output Values to the Scan System",
page 181.
For runtime reasons, the backward transformation
needs to subsequently be performed by the PC rather
than on the RTC6 PCIe Board itself. For this, all
correction and transformation settings currently
assigned to the scan system can be transferred from
the RTC6 PCIe Board to the PC by upload_transform.
Afterwards, an individual xy value pair or an
individual z value can be backward transformed by
transform.
By get_transform/get_transform_offset
get_waveform), an entire series of xy value pairs or
z values previously recorded by
set_trigger/set_trigger4/set_trigger8
backward transformed.
(1) Due to communication runtimes, the currently
returned actual positions are several clock pulses later
than the currently outputted control signals.
RTC6 boards
Doc. Rev. 1.0.21 en-US
8 Advanced Functions for Scan Head Control and Laser Control
get_values
or recorded
(1)
.
(see also
can be
Notes
• For some forward transformations, a backward
transformation is not possible:
Forward
transformation
Wobbel motion
(#2 on page 181)
Global coordinate
transformation
(#3 on page 181)
Processing-on-the-fly
correction
(#4 on page 181)
Coordinate transformations
(total matrix and offset) to the
x and y coordinates
(#5 and #6 on page 181)
Offset to the z coordinate
(#6 on page 181)
Clipping to the limits of the
controllable Image Field
(#7 on page 181)
2D Image Field correction /
3D Image Field correction
(#8 on page 181)
Gain and offset correction of
automatic self-calibration
(#9 on page 181)
Clipping to the maximum
possible control values
• Furthermore, backward transformation is not
possible if a noninvertable transformation matrix
has been defined during forward transformation
(notice: clipping to ±50 for each individual matrix
coefficient; see Chapter 8.2 "Coordinate
Transformations", page
invertability is already reported by
upload_transform.
Backward
trans-
formation
possible?
no
no
no
yes
yes
no
yes
yes
no
224). The non-
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