Denso BHT-500B User Manual page 48

When unable to successfully read barcodes...
Cause
When the illumination LED is focused on
the printed surface of the barcode from
Specular
directly above, there are times when
reflection
scanning is unsuccessful due to specular
reflection.
Scanning may be unsuccessful if the BHT
reading window is too close to or too far
Distance from
from the barcode, even when the barcode
barcode
is within the guide marker (laser light)
range.
Barcode surface Scanning may be unsuccessful if the
curvature barcode surface is curved.
Barcode surface Scanning may be unsuccessful if the
dirt barcode surface is dirty.
Barcode reading Scanning may be unsuccessful if the
window dirt barcode reading window is dirty.
Barcode scanning may be adversely
Direct sunlight,
affected
ambient light
brightness of the surrounding light.
by direct sunlight or the
Barcode Handy Terminal
Countermeasure
Change the BHT scanning angle and try again.
Move the BHT slowly toward or away from the barcode
and try again.
The guide marker range is only a guideline.
The displacement in the right direction in the diagram
increases as the BHT nears the barcode, and therefore
scanning should be performed so that the barcode comes
to the left side of the guide marker.
The barcode readable range is approximately 10 cm when
the scanning distance is 16 cm.
Readable range:
approx. 10 cm
Guide marker
Scan the barcode at the center of the barcode reading
window.
Wipe the dirt from the barcode and try again.
Blow any dust away with an airbrush, and then gently
wipe the reading window with a cotton swab or similar soft
object.
Perform barcode scanning away from direct sunlight. Try
adjusting the brightness of the surrounding light when
scanning indoors.
Scanning distance:
approx. 16 cm
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