Welch Allyn SCANTEAM 2380 WAND Specifications download pdf (Page 18)

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Operational Description

2.5.3 Depth of Field

Depth of field is the maximum perpendicular distance from the scanner tip

to the bar code symbol surface at which the scanner is capable of operating

effectively. In general, most of the SCANTEAM 2380 scanners have a

depth of field of 0.065 inches (1.65mm) with a symbol appropriate for the

scanner.

A chart showing the relationships between depth of field, scanning aperture

and bar code density appears on page A–1.

In normal use, the wand is seldom held perpendicular to the surface of the

bar code symbol. Rather, an operator tends to tilt the scanner. Useable

scan angle is a function of tip geometry and depth of field. If the depth of

field is too small, the scanner may fail to operate at extreme tilt angles

(>35°).

2.5.4 Scanning Velocity

The wand will operate at scan velocities from 2 to 50 inches/second (5 to

127cm per second) when the minimum bar/space size exceeds 7 mils

(0.18mm).

2.5.5 High Density vs Low Density Bar Code Symbols

Bar code density is a measure of the number of characters in a linear

measure of bar code. The standard of measure is normally given in terms

of the “X” dimension, the width of the narrowest bar code element. As bar

code density increases, the width of the narrowest bar code element

decreases. The scanning aperture should always be smaller than the

narrowest element to assure optimum resolution and the generation of a

digital signal which accurately represents the bar code.

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Welch Allyn SCANTEAM 2380 WAND Specifications Page 18