MATRIX 300™ REFERENCE MANUAL
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7
7.5.6 Extending DOF Using Alternative Acquisition Group (Input Select)
NOTE:
Do not use Interactive mode in VisiSet™ to set this feature.
Multiple Image Acquisition Settings assigned to different Acquisition Groups (
Standard
and
Alternative
) can be configured and enabled to extend the reader's depth of field. The specific
Acquisition Group (
Standard
or
Alternative
) is selected prior to the reading phase so that only
the correct group setting will be applied to the entire reading phase.
When only two Image Acquisition Settings are used to extend DOF, (one in each group), this
effectively allows switching DOF while keeping the lens refocusing delay outside the reading
phase.
This feature is recommended for high speed applications.
NOTE:
Within each group, if more than one Image Acquisition Setting is
enabled they will be cycled as in the case where
Alternative Group Select
is
disabled.
Example:
Read a 15 mil Data Matrix ECC 200 code covering a range from 140 to 320 mm (see
15 mil
reading diagram
) at an application speed of 1 m/s. The reading distance range is too long to
be covered by a single acquisition setting, so two acquisition settings could be used in which
the first has a
Reading Distance of 195 mm
and is assigned to the
Alternative Acquisition
Group
, and the second has a
Reading Distance of 300 mm
and is assigned to the
Standard
Acquisition Group
.
By assigning the
Alternative Group Select
parameter to a proximity sensor (i.e. S3Z)
mounted at least 150 ms before the
Acquisition Trigger
and connected to an input (i.e.
Input 2), the correct DOF can be selected by enabling the correct group.
As an example, for a conveyor speed of 1 meter/second the
Alternative Group Select
trigger must be placed at least 150 mm before the reading phase start (Ext. Trigger).
The proximity sensor must be calibrated to trigger on packs in the near zone (140-215 mm)
and therefore selects the
Alternative Group
with the Image Acquistion setting relative to the
195 mm Reading Distance. Packs farther away do not trigger the proximity sensor and so the
Standard Group
is selected with the Image Acquistion setting relative to the 300 mm
Reading Distance.
The settings overlap in the range 210-220 mm and can be read by either one.
In this way the effective reading DOF covers the 140 -320 mm distance.
Summary of Contents for Matrix 300
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