Rockwell Automation 2755-L7, -L9 Scanners - Manual (Page 42)

Glossary
G–4
diverging beam
A beam of light that is optically controlled so the light extends in different
directions from the source.
E
EAN
Acronym for European Article Numbering System, the international standard
bar code for retail food packages.
edge error
Irregularities with respect to the average edge of an element.
element
1) A single binary position in a character. 2) Dimensionally the narrowest
width in a character, bar or space.
encoded area
The total linear dimension consisting of all the characters of a code pattern,
including start/stop characters and data.
extraneous ink
Ink in a scan area not intended to be there.
F
first read rate
The first read rate is the percentage of bar code symbols that are read with the first
pass of the bar code wand under ideal conditions. Bar code symbols should have a
first read at least 90% of the time. A first read rate of less than 90% usually means
that either the bar code symbols or scanning device need some type of adjustment or
modification. This does not mean that a system which has a first read rate of less
than 90% is unacceptable.
G
guard bars
The bars at the ends and center of a UPC and EAN symbol. They ensure a
complete scan of the bar code.
H
hand held scanner
Refers to any scanning device that must be held over the bar code symbol.
height–of–scan
The maximum vertical scanning dimension of a moving beam scanner at a
specific distance from the face of the scanner.