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Chapter5 When Unable to Successfully Read Codes
Specular
reflection
Distance from
code
Curved material's
surface of
barcodes
Missing barcodes
by debris
Soiled reading
window
Reading in
sunlight or
inappropriate
brightness
Cause
Mounting the BHT perpendicular to a code
may cause specular reflection. This may
lead to no-read results.
No-read results can occur if the BHT is
positioned too close to or too far from a
code within a possible read distance.
No-read results can occur if the material's
surface of the barcode is excessively
curved.
Debris can obstructs barcode elements
from the view of the BHT.
No-read results can occur if the reading
window has obstruction such as dust or
debris.
No-read results can be caused by code
reading in sunlight or environment with
inappropriate brightness.
Countermeasure
Adjust the position of the BHT
relative to the code and scan again.
Gradually change the mounting
position of the BHT relative to the
code so as to find an appropriate
focal distance.
Ensure that the reading window is
mounted at center relative to the
code while scanning.
Remove any obstruction of the
barcode and scan again.
Blow out any contaminants with an
airbrush; gently wipe the window
with a soft, dry cloth.
In outdoor use, ensure to avoid
environment where the BHT
exposes to sunlight while scanning.
In indoor use, ensure to scan
barcodes in environment with
appropriate brightness for decoding.
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