Scanlab RTC6 PCIe Board - Determining Reference Values; Calibration During the Application; Automatic Self-Calibration

RTC6 boards
Doc. Rev. 1.0.21 en-US
8 Advanced Functions for Scan Head Control and Laser Control
277
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8.10.3 Determining Reference Values
The reference values are determined by auto_cal
( Command = 0). This starts the measurement routine
for determining the current Home-In positions. These
are then the reference values for later calibrations
with auto_cal( Command = 1 or 3 ). Immediately after
determination, they can be read out by get_hi_pos
and are available for customer-specific calibration,
see Section ”Customer-Specific Calibration”,
page 278. The reference values are stored in the Flash
Memory of the RTC6 board. This guarantees that the
reference values are available even after a restart.
Notes
• After auto_cal( Command = 0), the
galvanometer scanners are in the same real
Image Field position as before the command.
• The reference values should be determined when
the machine is set up, for example, when the
scan system is installed or exchanged. When
exchanging the scan system, for which reference
values have already been determined earlier and
read out by get_hi_pos, these reference values
can be transferred directly to the RTC6 board by
write_hi_pos.
• Reference values should be determined under
conditions (ambient temperature, load) typical
for the application and after the overall system
has fully attained its operating temperature. The
reference values should always be determined
only after a warm-up time of more than 20
minutes and not before the TempOK signal has
been activated.
• Execution of auto_cal( Command = 0 ) typically
lasts up to 10 seconds.
• Storing the reference values takes several ms and
interrupts the 10 µs clock cycle of the DSP. For
scan systems with clock cycle monitoring
(interlock), this should be temporarily
deactivated.
8.10.4 Calibration During the
Application
Automatic Self-Calibration
Automatic self-calibration of the scan system during
an application can be executed with
auto_cal( Command = 1 ).
This starts a measurement routine for determining
the current Home-In positions. From the deviations
from the stored reference values (see Chapter 8.10.3
”Determining Reference Values”, page 277)
determined in the process, gain values and offset
values are calculated and set separately for the x axis
and y axis.
This drift compensation is effective immediately. It is
valid until:
• auto_cal( Command = 1 ) is called again
• it is switched off
– by auto_cal( Command = 2 )
– after load_program_file
Notes
• After auto_cal( Command = 1 ) the
galvanometer scanners are in the same position
in the real Image Field as before the command.
• The calibration routine started with
auto_cal( Command = 1 ) typically lasts
1…2 seconds (depending on the strength of the
drift). An ASC hardware check is automatically
performed, if auto_cal( Command = 0 or 4 ) has
not been executed prior to the first time call of
auto_cal( Command = 1 ). This extends the
execution of auto_cal by a few seconds.