Datalogic AV500, Руководство по продукции

Страница: 313 / 324

READING DIAGRAMS
PRODUCT REFERENCE GUIDE
293
READING DIAGRAMS
The following reading diagrams are to be considered as references and are given for typ ‐
ical performance at 25°C using high quality grade A symbols: Code 128 (1D code) and ‐
Data Matrix ECC 200 (2D code) from the Test Charts provided with the reader.
• Testing should be performed with the actual AV500 using application codes in
order to evaluate whether maximizing application performance requires adjust
‐
ments to the HW/SW configuration with respect to the Reference Conditions
given under each diagram.
• The focus distance and reading distance ranges are measured from the surface of
the mounting screws on the back of the unit.
• When defining a HW/SW configuration for the AV500 for conditions different from
those of the reference diagrams, it is suggested to keep in mind the following
rules:
Changes in the diaphragm aperture influence the depth of field (reading distance range)
and the luminosity of the image. Increasing the diaphragm aperture by one stop (i.e.
from F/8 to F/5.6 or from F/11 to F/8) doubles the luminosity of the image, but can cause
significant reduction in the reading distance range.
Changes in Exposure Time act directly proportional to the luminosity of the image and
inversely proportional to the maximum code reading movement speed. Consequently,
reducing the
Exposure Time by half, reduces the luminosity of the image by half but
doubles the theoretical code reading movement speed.
Changes in Gain act directly proportional to the luminosity of the image. Increasing the
Gain value however, can reduce the quality of the acquired image. For example, for the
purpose of only changing the luminosity of the image, the following three adjustments
are equivalent: increase the diaphragm aperture by one stop; double the
Exposure
Time ; double the Gain .