Rockwell Automation 2755 AtomScan Bar Code Reader User Manual
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Glossary
G–3
Publication 2755-6.9
Operational Commands – Serial commands from the host to the
reader that control current operating parameters, counters, master
label operations, and program management that are not stored in
non-volatile RAM.
Package Detector – A photo electric device used to sense to
presence or absence of a package.
Picket Fence Label Orientation – A bar code label in which the
bars are perpendicular to the label’s direction of travel.
Pitch – Label (or reader) rotation around the center a line
perpendicular to the label’s bars.
Point-to-Point – A protocol consisting of a single communications
event, typically used to connect a bar code reader to a terminal or
host computer.
Port – Logical circuit for data entry and exit. (One or more ports
may be included within a single connector.)
Protocol – The rules for communication between devices, providing
a means to control the orderly flow of information between linked
devices.
Quiet Zones – Specified “clear” (nonprinted) areas immediately
before and after the bar code symbol. The area is usually white (for
black and white bar code) and at least 10 times the width of the
narrowest bar, as measured in thousands of an inch. The zones can
be other than white as long as their densities remains consistent and
they have the required contrast relative to the bars.
RAM – Random Access Memory. Memory that is lost after power is
recycled to the unit.
Read Cycle – A programmed period of time or condition during
which the reader will accept bar code label input.
Reader – A scanning device that is comprised of a scan head and a
decoder integrated in one package.
Read Range – The distances in which a label can be reliably read, as
measured from the front of the reader. See Depth of Field.
Reflectance Threshold – A user-defined setting of reflection (a few
digits higher than an empty space reading) that is a
point-of-reference for the MS-sensor. A reading lower than the
threshold indicates that a package is not present whereas a higher
reading indicates the presence of a package.