MLT-DPM Illuminator
Product Reference Guide 197
Examples for DPM Applications
In the example below, two Data Matrix codes etched onto a plastic reflective
surface must be read.
With all four LED sectors enabled (Example A), the code is not readable due to
t
he LED reflections on the code surface. With different Image Settings in which
the Bottom-Right sector is turned off (removed from the parameter combination
- Example B) and the Top-Left sector is turned off (removed from the parameter
combination - Example C), the code is illuminated by the other LED sectors
without the reflections on the code surface.
Example A
INCORRECT illumination
Example B
GOOD illumination on
Left code
Example C
GOOD illumination on
Ri
ght code
Please consider that, like the
Diffused Red Illuminator
, when using
MLT-DPM
Central LED Group
to illuminate surfaces with linear machining flaws, the well-
lighted area depends on the direction of the machining flaws with respect to the
illuminator’s LED sectors, irrespective of the reading distance.
Clearly, this characteristic fixes the upper limit o
f the code dimensions
compatible with the use of the
MLT-DPM
. In reality, it is an actual limit of the
usable part of the field of view. Therefore, this limit must be taken into account
during the feasibility analysis of the solution, including the eventual positioning
variation of the codes with respect to the center of the reader’s field of view.
The arrangement of the LED sectors allows obtaining a well-lighted area even
wh
en the direction of the machining flaws is changed.
Refer to the following images for the dimension of lighted area illuminated by
th
e different LED Groups.
Figure 96 - Color Photo of Code
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