Scanlab RTC 5 PC Interface Board - 8.1.9 Fault Diagnosis and Functional Test; 8.2 Coordinate Transformations

RTC
®
5 PC Interface Board
Rev. 1.9 e
8 Advanced Functions for Scan Head and Laser Control
161
innovators for industry
8.1.9 Fault Diagnosis and Func-
tional Test
If a problem occurs, the versatile status return func-
tions of the iDRIVE
®
scan system can be used for scan
system diagnosis, too. These functions allow to read
for instance
• the current operating state
• the operating state at the moment of the most
recently occurred operation interruption and
• an event code, indicating which particular event
caused the scan head to enter a temporary or
permanent error state.
To verify that data transfer capability between the
RTC
®
5 and a scan system is intact,
control_command can transmit an 8-bit value –
separately for each axis– to the scan system. Subse-
quently, a 20-bit value will be returned on the corre-
sponding status channel: If data transfer is error-free,
then the upper 8 bits of the returned 20-bit value will
be identical with the originally sent 8-bit value, and
the next lower 8 bits will be identical with the
complement of the sent 8-bit value.
These 20-bit values will be returned until the
control_command is used to select another return
data type (see section "Configuring Status Return
Behavior" on page 153).
To facilitate – after a data transfer verification – resto-
ration of the status return behavior in effect prior to
the data transfer verification, the control_command
allows the prior data type to be temporarily stored for
later retrieval.
8.2 Coordinate Transformations
For precise set-up of the scan system relative to the
image field (if the “second scan head control” option
has been enabled, two scan heads can be adjusted
relative to a common image field), a linear coordinate
transformation can be defined (separately for the
primary and secondary scan head connectors) for all
X and Y output coordinates (x|y) defined by vector or
arc commands:
The (2 x 2) total matrix M is thereby automatically
calculated by the RTC
®
5 as a product of a scaling
matrix M
S
, a rotation matrix M
R
and a general trans-
formation matrix M
T
:
The coefficients of the three matrices (M
S
, M
R
and
M
T
) and the offset values (x
0
|y
0
) can be individually
defined for the primary and secondary scan head
connector.
The offset (x
0
|y
0
) is set via set_offset or
set_offset_list.
For 3-axis scan systems, set_offset_xyz or
set_offset_xyz_list enables setting of an offset z
0
for
the Z coordinate, too (z
0
has the opposite effect of
set_defocus or set_defocus_list). The following
applies:
The coefficients of the scaling matrix M
S
are set via
set_scale or set_scale_list using a scaling factor k
that is common to both axes:
The coefficients of the rotation matrix M
R
are set via
set_angle or set_angle_list by specifying a rotation
angle (mathematical definition: positive angles
produce counterclockwise rotation):
x'
o
y'
o
M
x
o
y
o

x
o
y
o
+=
MM
T
M
R
M
S
=
z'
o
zz
o
+=
M
S
k 0
0 k
=

M
R
cos
o
– 
o
sin–
sin
o
– cos
=