Omron V550-A20 Page 68 Operation Manual Download

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V550-A20 Operation Manual

Glossary

graphic element. Used as part of the organization, control, or
representation of data.

Check Character -

A character (usually at the end of the code)

that is used to perform a mathematical check to ensure the
accuracy of a scan of the bar code.

Code Orientation

- The relationship of the bar code with

reference to the bar code reader’s reading zone. Typical code
orientations are Ladder and Picket Fence.

Code Length -

The length of the bar code measured from the

start of the first bar to the end of last bar.

Code Placement -

Variation in code placement affects the ability

of a scanner to read a code. The terms Tilt, Pitch, and Skew deal
with the angular variations of code placement in the X, Y and Z
axes. Variations in code placement affect the pulse width and
therefore the decoding of the code. Pulse width is defined as 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. Tilt, pitch, and skew impact the pulse width of the
code.

Changes to this code presentation cause the bar codes to appear
smaller to the scanner which results in a smaller pulse width.
Each of these variations has a different effect on a scanner
reading these codes and the combination of the variations leads
to more complicated effects.

Tilt=0, Pitch=0, Skew

Code Quality

- The number of scans successfully decoded

during a read cycle.

Communications Protocol

- The rules governing exchange of

information between devices connected together on the same
communications line.

Conveyor Speed -

The speed that the conveyor is moving

measured in feet per minute. Conveyor speed directly impacts the
time that the code is in front of the scanner; therefore, it affects
the number of reads that are possible.

(Carriage Return)

An ASCII or EBCDIC control character

that moves the cursor or print mechanism to the left margin.

CTS

(Clear to Send) - The Modem interface signal that indicates

to the DTE device to begin transmission.

Depth of Field

- The distance between the maximum and

minimum plane in which a symbol can be read. This range is from
the specified optical throw to the far reading distance.

Dot Matrix Printer

- A dot matrix printer is an impact printer that

consists of a series of pins arranged in an array. The pins strike
an inked ribbon against the label stock to form the bar code and
characters. This is the most common type of printer used to print
labels on-demand. Some dot matrix printers use a moving print
head and stationary stock. The print head moves across the label,

printing one dot at a time, to complete one line. The print head
then begins printing the next line. Other dot matrix printers use a
stationary print head. These printers typically print one line at a
time and are therefore much quicker than a printer with a moving
print head.

Common Problems with dot matrix printing:

The

printed ink (bars) tends to expand or “bleed”. This causes the size
of the bars of a code to expand while shrinking the spaces. There
tends to be small gaps between pins of a dot matrix printed bar.
This can lead to problems with scanners because these gaps can
appear as spaces. Ribbon wear is a factor when printing dot
matrix codes. If a printer uses a circular type ribbon (ribbon is
used over and over again) the contrast of the bar code diminishes
over time. A bar code printed with an old ribbon can be more
difficult to read than one printed with a new ribbon.

Benefits of

dot matrix printing:

It is inexpensive to print bar codes using dot

matrix printers.

Downloading

- The process of sending configuration parameters,

operating software or related data from a central source to remote
stations.

DRX (Data Reconstruction)

- A technology that collects,

reconstructs, and decodes partial scans to provide valid bar code
data.

DSR

(Data Set Ready) - An RS-232 modem interface control