Rockwell-automation 2755 AtomScan Bar Code Reader Uživatelský manuál stáhnout pdf (Strana 24)

3–4 Designing Your Scanner System

Publication 2755-6.9

Picket Fence

In picket fence orientation, the symbol can be read the whole time it

is in the read range, rather than being limited by the height of the bar

code. However, picket fence allows scanning of only a small part of

the whole symbol. Slight imperfections such as extraneous ink or

voids can cause misreads or non-reads. The quality of data in picket

fence orientation can be improved by any of the following.

• Make sure the printing on the symbol is of good quality.

• Tilt the scan line slightly to allow a larger part of the symbol to be

scanned as it passes through the scan line.

Direction

of Travel

Direction

of Travel

Reader

Step Ladder

In general, step ladder orientation is preferred over picket fence

orientation because each scan covers a slightly different part of the

symbol. This means that:

• imperfections in the symbol are less liable to prevent a successful

read, and

• symbol placement is not as critical.

Direction of

Travel

Direction of

Travel

Reader

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Rockwell-automation 2755 AtomScan Bar Code Reader Uživatelský manuál Strana 24