Rockwell Automation 2755 Atomscan Bar Code Scanner - Manual (Page 13)

Chapter 3
Designing the System
3–2
There are two basic types of bar code symbols.
One-dimensional
The one-dimensional bar code symbols have one row of bars and spaces.
These were among the first to be developed. Examples that can be
successfully scanned by AtomScan scanners are:
•
Code 39
•
Code 128
•
Interleaved 2-of-5
•
UPC
•
EAN
Example of
UPC-A Bar
Code Symbol
•
Pharmacode
Two-dimensional
Two-dimensional bar codes are also referred to as “stacked bar codes”,
because they look like standard, one-dimensional bar code symbols stacked
tightly together. Examples of two-dimensional symbols are:
•
PDF417
•
Code 16K
•
Code 49
Example of
PDF417
Note: Two-dimensional symbols generally cannot be successfully
scanned by AtomScan scanners.
Narrow Element Width
It is very important to know the Narrow Element width of the target symbol
when selecting and applying bar code scanners. The Narrow Element is
defined as the narrowest bar or space in the symbol. All narrow bars and
narrow spaces would be the same width if perfectly printed. However this is
seldom true. Measure the narrowest bar and space and use the smaller
dimension as the Narrow Element Width, to determine expected read
capability.
Narrow Bar Narrow Space
Bar Code Symbols