Danfoss VLT Series Programming Manual page 75

Servo Drive Operation
Mandatory/
optional
Attribute
(+default
value)
input M
mode M
threshold M
minLength M
maxLength M
Table 2.45 Attributes for rectMark Search
Exit: Pattern detection
Just like the search for a rectangle mark, also the search
for a pattern is used for alignment, depending on a sensor
signal. In contrast to the rectangle mark, here it is possible
to search for any mark. Therefore, it is necessary to
download the reference signal to the axis together with
the CAM profile. A pattern search can only be done using
an analog sensor.
The behavior of the search for pattern exit condition is
more or less equivalent to the search for a rectangle mark
(see Illustration 2.113). As soon a pattern is recognized, the
axis proceeds with the next segment. In addition to the
reference pattern, the axis only needs a threshold for the
expected correlation. It is usually placed in the middle
between the highest disturbing signal and the expected
desired signal.
The time at which the pattern is found, depends on the
position of the pattern. The black line shows an example
for the case that the pattern is found right at the point in
MG36D102
Programming Guide
Value range/
Description
allowed values
1/2 Selects if the
st nd
1 or the 2
digital input is
affected.
Analogue/ Specifies the
digital signal source.
Allowed values
are analog or
digital.
Float: [-100; Threshold for
100]% the sensor
signal in %.
Negative
values are used
for inverse
mark polarity.
Integer: 0 to Specifies the
maxLength maximum
length that is
recognized as
a mark; Given
in number of
samples.
Integer: Specifies the
minLength to maximum
65535 length that is
recognized as
a mark; Given
in number of
samples.
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time that is marked with a black arrow. The position of the
succeeding node determines the latest point in time when
the search is aborted. If the pattern is found before
reaching the succeeding node, the axis proceeds with the
following segment right after the pattern is found, that
means before the succeeding node is reached.
Proceeding to the next segment always takes place in
relation to the end of the pattern. When changing the
position or the length of the reference pattern, the
position where the axis stops is also changed.
<pattern input="1" threshold="50" subsample="1"
checkLength="1"/>
Mandatory/
optional
Attribute
(+default
value)
input M
threshold M
subsample
M
checkLength M
Table 2.46 Attributes for Pattern Search Action
Each CAM profile has 1 pattern file associated. This means
that, if there is >1 pattern search action inside 1 CAM, they
would use the same pattern file.
The pattern information is transmitted to objects 0x3830 to
0x3837 (see chapter 7.14.6 Parameters: CAM Pattern 1–8
(0x3830–3837)).
Value range/
Description
allowed values
1/2 Selects if the
first or the
second digital
input is
affected.
Float: [-100; Threshold for
100]% the minimum
correlation in
%. Negative
values are used
for inverse
mark polarity.
0–4 Subsampling
factor for
sensor input.
0: 16 kHz or
20 kHz
1: 8 kHz or
10 kHz
2: 4 kHz or
5 kHz
3: 2 kHz or
2.5 kHz
4: 1 kHz or
1.25 kHz
Integer: [1; Number of
1000] consecutive
descending
correlation
samples after
correlation
maximum.
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