Rockwell Automation 2755 AtomScan Bar Code Reader - Manual (Page 26)

3–6 Designing Your Scanner System
Publication 2755-6.9
Skew
A symbol is skewed when the ends of the symbol’s bars are not at
the same distance from the reader. The symbol can be read if the
distance of both ends of the bar are within the reader’s read range,
and the skew is less than
40 degrees from the centerline. Unlike
pitch, skew does not affect the read range.
Note: Some skew is necessary to prevent strong reflected light
(specular reflection) from interfering with a successful read. A skew
between 20
°
-30
°
is ideal. Or skew may be combined with pitch to
give the following angle.
20 _-30_
20 _-30_
Reader between 20 _ and
30
_above or below the symbol
The readers can read bar code symbols at various distances
depending upon the type of reader and the narrowest bar code
element width (width of smallest bar or space). With picket fence
orientated labels, scan width is a factor in determining the time it
takes to read a bar code symbol.
Catalog Number
Minimum Bar Code
Width
Read Range
Maximum Scan
Width
2755-LS7-SA, 5.0 mils (0.13 mm) 2.0 to 3.1 in. (5.08 to 7.87 cm) 2.1 in. (5.33 cm)
2755-LS7-RA 7.5 mils (0.19 mm) 2.0 to 4.0 in. (5.08 to 10.2 cm) 3.6 in. (9.14 cm)
2755-LS7-SB, 7.5 mils (0.19 mm) 2.5 to 5.5 in. (6.35 to 14.0 cm) 4.0 in. (10.2 cm)
2755-LS7-RB 10 mils (0.25 mm) 2.0 to 6.5 in. (5.08 to 16.5 cm) 5.0 in. (12.7 cm)
15 mils (0.38 mm) 2.0 to 7.5 in. (5.08 to 19.0 cm) 6.0 in. (15.2 cm)
20 mils (0.51 mm) 2.0 to 10.0 in. (5.08 to 25.4 cm) 7.0 in. (17.8 cm)
30 mils (0.76 mm) 2.0 to 10.0 in. (5.08 to 25.4 cm) 7.0 in. (17.8 cm)
40 mils (1.02 mm) 2.0 to 10.0 in. (5.08 to 25.4 cm) 7.0 in. (17.8 cm)
2755-LS7-SBV, 7.5 mils (0.19 mm) 1.25 to 4.0 in. (3.18 to 10.2 cm) 4.0 in. (10.2 cm)
2755-LS7-RBV 10 mils (0.25 mm) 1.0 to 5.0 in. (2.54 to 12.7 cm) 5.0 in. (12.7 cm)
15 mils (0.38 mm) 1.0 to 6.0 in. (2.54 to 15.2 cm) 6.0 in. (15.2 cm)
20 mils (0.51 mm) 1.0 to 8.5 in. (2.54 to 21.6 cm) 7.0 in. (17.8 cm)
30 mils (0.76 mm) 1.0 to 8.5 in. (2.54 to 21.6 cm) 7.0 in. (17.8 cm)
40 mils (1.02 mm) 1.0 to 8.5 in. (2.54 to 21.6 cm) 7.0 in. (17.8 cm)
Determining Read Range