Scanlab RTC6 PCIe Board - Automatic Determination of the Jump Delay Table

RTC6 boards
Doc. Rev. 1.0.21 en-US
8 Advanced Functions for Scan Head Control and Laser Control
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Automatic Determination of the Jump Delay
Table
If previously Jump Mode has been successfully
enabled and activated by
set_jump_mode( Flag = 1 ), an automatic
determination of the Jump Delay table can be started
by load_jump_table_offset( Name = NULL ).
For automatic determination, “Automatic Laser
Control“ is deactivated, the data type to be returned
by the scan system is set to target position and the
tuning set to the Jump tuning that had been defined
by set_jump_mode (the original settings are
restored when load_jump_table_offset completes).
For automatic determination, several diagonal jumps
of varying lengths are performed. For each jump, the
target position returned by the scan system is
recorded by set_trigger (not: set_trigger4,
set_trigger8) and retrieved by get_waveform. The
data is analyzed for the timepoint at which the
specified position tolerance ( PosAck parameter) has
been last exceeded, that is, when the target position
persistently remained in the jump target positional
range ± PosAck . This value is then reserved as the
Jump Delay value associated with the corresponding
jump length.
Notes
• Before automatic determination, you must
absolutely switch off the laser.
• Data recording requires execution of a list with a
total of six commands. The commands are
automatically written to RTC6 List Memory and
processed. The parameter ListPos indicates the
position in RTC6 List Memory (“list 1” or “list 2”)
in which storage is to occur. This position should
be such that any previously entered
list commands can be harmlessly overwritten.
• For automatic determination, the longest jump is
performed first, followed by increasingly shorter
jumps (with a maximum of up to 16 different
jump lengths). For the first (longest) jump length
(jump across the entire image diagonal), the
measurement period is specified by the
parameter MaxDelay [10 µs].
MaxDelay should be chosen to be adequate but
not significantly larger than the Jump Delay for
the longest jump. A larger MaxDelay increases the
total required execution time. With
MaxDelay = 500, the total execution time for
automatic determination is typically a few
seconds.
• For statistical noise reduction, 4 identical jumps
are performed for each jump length and the
results averaged. Additionally, the values for each
individual measurement are low-pass filtered (2-
point smoothing). This permits selection of a
position tolerance PosAck that can also be
somewhat (but not substantially) under the
expected noise level but note that only whole
multiples of 16 are returned with an
XY2-100 Converter (Accessory). Here, a noise
level of ±3 × 16 bits can be expected).
• If the PosAck range is not persistently reached
within the measurement period, then MaxDelay
becomes the determined Jump Delay.
• If the determined Jump Delay is smaller than
MinDelay , then MinDelay becomes the determined
Jump Delay and the measurement terminates.
Then, shorter jumps are no longer performed and
MinDelay is also the determined Jump Delay for
these shorter jump lengths. A longer MinDelay
reduces the total execution time for automatic
determination.