Symbol SE 2223, Integration Manual

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3-9
SE 2223 Specifications
Decode Zone
The decode zone is a function of various symbol characteristics including density, print
contrast, wide to narrow ratio and edge acuity. Width of field at any given distance must be
considered when designing a system.
Usable scan length is calculated as follows (assuming 10% on each side of scan line is not
decodable):
L = 1.8 x (D+d) x Tan (A/2)
Where:
D = Distance (in inches) from the front edge of the housing.
d = The housing’s internal optical path (in inches) from the x mirror to the front
edge of the housing.
A = Scan angle in degrees (34°).
So:
L = 1.8 x (D+d) x Tan 17°
Note: Usable scan length determined by above formula, or 90% of scan
line at any working distance.
The calculations above are based on good quality symbols in the center of the working
range.
For 2D PDF417 symbols the height of the symbol must be considered to determine if the
scanner can open in the Y direction sufficiently to read the symbol. The formula is the same
as above except that the Y angle is 12.5
°.
L = 1.8 x (D + d) x Tan (A/2)
L = 1.8 x (D + d) x Tan 6.25°
If the above equation yields a greater height than the symbol height, the scan engine
automatically adjusts the Y pattern to fit the symbol. If the symbol is taller, a manual swipe
in the Y direction may be necessary to read the symbol.