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5
V550-A20 Operation Manual
Glossary
5
Peripheral Device
- An internal or external device, such as a
printer, a disk drive, or a keyboard, connected to a computer.
Photoelectric Sensor
- Used as a presence detector to identify
objects in the bar code reader’s reading zone. A retroreflective
photoelectric sensor emits a beam and is used with a reflector to
create a photoelectric circuit. When the beam is blocked by an
object, breaking the circuit, a signal called TRIGGER is sent to
the bar code reader.
Picket Fence Orientation
- Presentation of a bar code such that
the bars are positioned vertically on the product, causing them to
appear as a picket fence. The first bar will enter the scan window
first.
SCAN LINE
DIRECTION OF TRAVEL
Pitch
- Rotation of a code pattern about the X-axis. The normal
distance between center line or adjacent characters.
Polarized Laser
- A specialized laser source used in high glare
environments.
Polling
- A means of controlling devices on a multipoint line.
Protocol
- A formal set of conventions governing the formatting
and relative timing of message exchange between two communi-
cating systems.
Pulse Width -
A change from the leading edge of a bar or space
to the trailing edge of a bar or space over time. Pulse width is also
referred to as a transition.
Queue
- Data held in a buffer until it is used or transmitted.
Quiet Zone
- Required distance before the first bar and after the
last bar of the code that must be free of marks or printing.
Raster -
The process of projecting the laser beam at varied
angles spaced evenly from each other. Typically, the mirror wheel
surfaces are angled to create multiple scan lines instead of a
single beam.
Raster Mirror Wheel
- The standard mirror wheel forms the laser
line that is projected from the scanner. Although the mirror wheel
projects 8 separate lines (for an 8-sided mirror wheel), the speed
of the sweep makes it appear that it is actually one line. This type
of mirror wheel is adequate for a
ladder
orientation because the
laser line will pass from the bottom to the top of the code. For a
picket fence
orientation the standard mirror wheel is not always
adequate. One problem facing the
picket fence
orientation is that
the same portion of the code is being repeatedly scanned. If the
printing quality at this point is not good the label may not be
scanned even though other parts of the label are good. Another
problem for a
picket fence
orientation is the placement of the
label. If the placement is off enough a single scan line will not
read all the bar codes presented to the scanner.
Read Zone
- Area in front of the scanner’s window in which the
bar code should appear for scanning. This zone consists of the
scan window and the raster width (if used).
Reflectance -
The amount of light returned from an illuminated
surface.
Request To Send
(RTS) - An RS-232 modem interface signal
which indicates that the DTE has data to transmit.
Resolution
- The narrowest element dimension which can be
distinguished by a particular reading device or printed with a
particular device or method.
Response Time
- The elapsed time between the generation of
the last character of a message at a terminal and the receipt of
the first character of the reply. It includes terminal delay and
network delay.
RPM
- Revolutions per minute.
RS-232
- Interface between data terminal equipment and data
communication equipment employing serial binary data inter-
change.
RS-422
- The Electronic Industries Association standard that
specifies the electrical characteristics of balanced voltage digital
interface circuits.
RS-485
- The Electronic Industries Association standard that
specifies the electrical characters of generators and receivers for
use in balanced digital multipoint systems.
Scan
- A single pass of the laser beam over the code or a portion
of the code. The search for a bar code symbol that is to be
optically recognized.
Scan Area
- The area intended to contain a symbol.
Scan Window
- The usable length of the scanning beam that
may detect the bar codes. The scan window is perpendicular to
the depth of field.
Scanner
- An electronic device that optically converts printed
information into electrical signals. These signals are sent to the
decoder logic.
Scanner Orientation
- Relationship of the scan head with
reference to the bar code’s location on products. The scan head
must be set up to insure that all code bars and spaces are
bisected at the same time. Typically, either side read or top read
is used for picket fence or ladder code orientations.
Self-checking
- A bar code or symbol using a checking algorithm
which can be independently applied to each character to guard
against undetected errors.
Serial Transmission
- The most common transmission mode;
serial, information bits are sent sequentially on a single data
channel.
SERIAL ASYNCHRONOUS TRANSMISSION OF DATA
: The
V550-A20 is capable of communicating via the following inter-
faces: RS-232, RS-422, and RS-485.
Summary of Contents for V550-A20
Page 1: ...i V550 A20 Operation Manual V550 A20 Bar Code Reader Operation Manual Cat No Q01BAZ2...
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Page 26: ...12 V550 A20 Operation Manual Section 2 12 What to Do After Receiving the V550 A20...
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Page 66: ...18 V550 A20 Operation Manual Section 5 18 Appendices...