Rockwell Automation 2755-L7, -L9 Scanners - Manual (Page 48)

Glossary
G–10
scanning curtain
The effective reading area (width x height) of a moving beam scanner, which
is equal to its depth–of–field and height–of– scan at a specific operating
range.
scanning range
The combined distance of optical throw and depth of field.
self–checking
A bar code or symbol using a checking algorithm which can be applied to
each character to guard against undetected errors. Non–self–checked codes
may employ a check digit or other redundancy in addition to the data
message.
serial code
A bar code symbol typically used with a fixed beam scanner where the
scanning action is caused by the motion of the symbol past the scanning
head. The bits of the symbol are evaluated one at a time (serially).
skew
Rotation about the Y axis. Rotational deviation from correct horizontal and
vertical orientation may apply to a single character, line or the entire encoded
item.
space
The lighter element of a bar code
space encoding
See interleaved bar code.
special symbol/character
In a character set, a character that is neither a numeral, letter, or a blank: for
example, @ $ % ¢ & *.
spectral response
The variation in sensitivity of a device to light of different wavelengths.
specular reflection
Reflection of light from a surface at an angle equal but opposite to the angle
of incidence. See reflectance, specular.
spots
Ink or dirt spots within the spaces or clear area of a bar code which may
reduce first read rate.
start/stop character
A bar code character that provides the scanner with start and stop reading
instructions as well as code orientation.
step ladder orientation
A code pattern in which the overall coded area from start to stop is
perpendicular to the horizon. The individual bars appear as rungs of a
ladder.