RTC
®
5 PC Interface Board
Rev. 1.9 e
8 Advanced Functions for Scan Head and Laser Control
158
Experimental Determination of Jump Delay
Values
The scan system’s user manual typically specifies the
step response times for each jump tuning at selected
jump lengths.
To experimentally determine the step response
behavior, you’ll need to have the scan system perform
jumps of various lengths and query the resulting
position values via the status channel for analysis.
After you activate jump mode, perform the jumps by
using jump_abs or jump_rel commands (and the
desired jump tuning). The scan system should have
been previously set to return the actual-position data
type via control_command. You can then record the
latter via set_trigger/set_trigger4 and retrieve it via
get_waveform.
The determined jump delay values must be supplied
in an ASCII text file. If the step response behaviors of
both axes differ, then the higher of the two axes’
jump delay values should be supplied.
Notes on Loading Determined Jump Delay
Values
The load_jump_table_offset command loads a table
with jump lengths and jump delay values from an
ASCII text file. The text file can contain one or several
tables.
Each table can contain up to 50 data points
(Length Delay(Length)) for various jump lengths.
The RTC
®
5 applies linear interpolation to this data to
create the complete (internal) jump delay table
Delay(Length).
The following rules apply to tables:
• Each table must begin with the statement
(Caption)
[JumpTable<No>]
where
<No>
must be replaced by a nonnegative
integer which denotes the table number.
• If the table contains multiple
[JumpTable<No>]
entries with the same
<No>
, then only the instruc-
tions after the first entry will be used; instructions
that follow further entries will be ignored. Only
instructions up to the next ’[’ character (that is
not preceded by a semicolon) are used.
• Each data point (Length Delay(Length)) is
described by two instructions:
Length<n> = <LengthValue>
Delay<n> = <DelayValue>
where
<n>
must be replaced by an integer
(1
<n>
50) which denotes the number of the
data point. The
<Value>
numbers can be supplied
as (unsigned) floating point numbers. Use the
period
(.)
as the decimal separator.
• If the table contains multiple data points with the
same index
<n>
, then the most recently read one
will be used and the previous ones ignored.
• If the table contains multiple data points with the
same jump length value Length, then the data
point with the largest index
<n>
will be used and
the others ignored. Equality is checked to within
±0.01.
•For
<Value>
the following ranges apply:
0.0 Length 1048576.0
0.0 Delay(Length) 65535.0
Delay values are supplied in units of 10 µs, jump
lengths in bits.
• Each instruction must be in a separate line.
• Space characters and tabs within a line (e.g.
between ’
=
’ and
<Value>
) are ignored.
• Empty lines are ignored.
• Data points with invalid values are ignored.
• The data point of a particular index
<n>
is ignored
if the corresponding
Length<n>
and/or
Delay<n>
definition is missing.
• The semicolon ’;’ can be used for comments. All
characters in a line following a semicolon are
ignored.
• The instructions for data points in the table can
be ordered as desired.
• Indices for data point pairs in the table can be
selected as desired within the range [1…50] (the
table will then be automatically sorted by
ascending position values).
• If the table contains no valid data points, then the
command load_jump_table_offset will have no
effect (return value 1 or 13).
• If there is no entry of Length = 0.0, then one with
Delay
=Min(
Delay<i>
) will be inserted (the
smallest valid value encountered will be filled
downward). The same applies to
Length =524288.0 with Max(
Delay<i>
).
• If the specified text file contains only one valid
data point with
Delay<n> = D
, then the jump
delay table Delay(Length)
=D
(for the whole
jump length range) will be loaded.
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