Rockwell Automation 2755 High Performance VLD Scanner - Manual (Page 31)

3–18 Installation Considerations
Figure 3.13 further illustrates how a pitched symbol can change the
read range enough to require a different scanner.
Figure 3.13
Read Range and Symbol Resolution Changed By Pitch
3 inch (7.6 cm) symbol is pitched 30
°
.
This requires the read range to
extend an additional 1.5 inches (3.8 cm).
Apparent element width = 17.3 mils (44 mm)
Symbol’s Nearest
Elements are 18
inches (45.7 cm)
18 Inches (45.7 cm)
2755–LD4C1
19.5 Inches (49.5 cm)
Symbol’s Farthest
Elements are 19.5
inches (49.5 cm)
5
.13
10
.25
15
.38
20
.51
25
.64
30
.76
35
.89
40
1.02
45
1.14
50
1.27
5
12.7
10
25.4
15
38.1
20
50.8
25
63.5
30
76.2
35
88.9
40
101.6
45
114.3
50
127.0
Apparent Minimum Element W
idth
Mils
Millimeters
Inches
Centimeters
Read Range
(from scan window)
A
B
C
This is the new read range, 18 -
19.5 inches (45.7 - 49.5 cm).
Pitching the symbol reduced
the element width and extended
the read range.
The 2755-LD4B1 scanner is not
appropriate for this application.
Instead use the 2755-LD4C1.
This was the read range and
element width at 0
°
pitch.
Compensating for
Pitched Symbols