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V550-A20 Operation Manual
Glossary
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Front Read
- The scanner is mounted to read bar codes on the
leading edge of a box as it passes the scanner. In a front read
application, the scanner can be mounted above or on the side of
the conveyor.
Full Duplex
(FDX) - Simultaneous, two-way, independent
transmission in both directions.
Half Duplex
(HDX) - Transmission in either direction, but not
simultaneous.
Handshaking
- Exchange of predetermined signals between two
devices establishing a connection. Usually part of a communica-
tions protocol.
Height-of-Scan
- The maximum vertical scanning dimension of a
moving beam scanner at a specific distance from the face of the
scanner.
Helium Neon Laser
- The type of laser most commonly used in
bar code scanning. Because the laser beam is bright red, bars
must not be printed with red ink since they would be indistinguish-
able from the code’s background.
Ink Jet Printing
- Ink jet is a non-contact printer that projects
drops of ink at a printing surface. The sprayed drops are
controlled electronically to form a bar code.
Common Problems
with laser printing:
Its main restriction is that ink jet printing is
usually capable of printing only low density codes.
Benefits of
laser printing
: Because ink-jet printers are non-contact and non-
impact, they can print bar codes on a variety of contoured, rough,
and delicate surfaces. Capable of printing random or sequential
information on labels. Ink jet printers can print directly on cartons
and avoid the cost of label stock.
Input/Output Modules
- Since many scanners are operating in
environments that have electrical noise problems, it is helpful to
have equipment electrically isolated from other equipment. The
standard method for isolating inputs and outputs is through the
use of OPTICALLY ISOLATED INPUT/OUTPUT MODULES.
These flexible modules allow the scanner to control high voltage
outputs that are susceptible to noise. Since they are isolated from
each other the noise is not picked up in the scanner.
Omron PLC modules are available as input and output versions.
Maximum current is limited by the input modules. Input modules
can be used for photoelectric trigger inputs. Output modules are
commonly used to control diverters, alarms, external relays, etc.
Intercharacter Gap
- The space between two adjacent bar code
characters in a discrete code.
Interface
- A shared boundary defined by common physical
interconnection characteristics, signal characteristics and
meanings of interchanged signals.
Interleaved Bar Code
- A bar code in which characters are
paired together using bars to represent the first character and
spaces to represent the second.
I/O
(Input/Output) - The keyboard and a printer, are examples of I/
O devices. I/O activity is different from computational activity.
When a program sends a document to the printer, it is engaging
in I/O activity; when the program sorts a list of terms, it is
engaging in computational activity.
Jumper
- A wire that connects a number of pins on one end of a
cable only, such as looping back Request to Send from Clear to
Send pins 4 and 5.
Ladder Orientation
- Presentation to the scanner of a bar code
such that the bars are positioned horizontally on the product,
causing them to appear as a ladder. The ends of all bars will enter
the scan window first.
Laser Gun
- A hand-held non-contact laser scanner that is
usually activated with a trigger.
Laser Scanner
- An optical bar code reading device using a low
energy laser light beam as its source of illumination.
Laser Printing
- Laser printers use a pulsed or rastered laser
light source to positively charge an image on a dielectric cylinder
of an electrostatic printing mechanism. Toner used in the laser
printing process adheres to the charged portion of the cylinder.
This toner is then transferred to paper using heat.
Common
Problems with laser printing:
The labels are more expensive
than those used in dot matrix printers.
Benefits of laser printing:
Labels can be printed at various speeds. Laser printed bar code
labels are high quality and very accurate.
LCD (Liquid Crystal Display)
- A low-power display often used
for notebook computers. An LCD consists of a liquid crystal
solution between two sheets of polarizing material. An electric
current causes each crystal to act like a shutter that can open to
allow light past or close to block the light.
LED
(Light Emitting Diode) - A semiconductor generally made
from gallium arsenide, that can serve as a visible or near infrared
light source when voltage is applied continuously or in pulses.
LEDs have extremely long lifetimes when properly operated.
LF
(Line Feed) - An ASCII control character that moves the cursor
or print mechanism to the next line. (^J)
Memory Address
- A specific location, usually expressed as a
hexadecimal number, in the computer’s RAM.
Mil -
One thousandth of an inch (0.001 inch). Bars and spaces of
codes are commonly referred to as being a certain number of mils
wide. 1 mil = 0.0254 mm.
Misread -
The scanner incorrectly decodes a bar code as it
passes through the scan zone.
Moving-Beam
- Rather than using a stationary laser beam and
relying on product movement for a single scan, a multi-facet
mirror wheel and motor is used to ‘move’ the beam across the
code several times while in motion itself.
SCAN LINE
DIRECTION OF TRAVEL
Summary of Contents for V550-A20
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