Rockwell Automation 2755 High Performance VLD Scanner - Manual (Page 23)

3–10 Installation Considerations
Figure 3.9 shows the Usable Beam Length versus Distance for the
LD8 scanner. The black area is a no read area. The Usable Beam
Length (bottom of chart) is compared to the Reading Distance (top
of chart). The Usable Beam Length is approximately 20% less than
the projected beam length (10% on each end of the scan line). The
reading distance is measured from the scan window to the center of
the symbol.
Figure 3.9
LD8 Usable Beam Length ➀
3.3
8.4 5.5
14.1
7.8
19.7
10.0
25.3 12.2
30.9 14.4
36.6 16.6
42.2 18.8
47.8 21.0
53.4
Inches
Centimeters
Usable Beam Length (Nominal)
NA
NA
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
Inches
Centimeters
NA
NA
LD8 Reading Distance
Usable
Beam
Length
Reading Distance
= Catalog No. 2755-LD8
= No Read Area
➁
50
127.0
23.3
59.1
➁ Measured from the scan window to the center of the bar code symbol.
➀ Usable Beam Length for LD8 Scanners = 0.443 x (Reading Distance + 2.5 inches)
To estimate the Usable Beam Length:
•
Determine the distance from the window of the scanner to the
center of the bar code symbol. This is your Reading Distance.
•
Locate your Reading Distance on Figure 3.9. The reading
distances are displayed across the top of the chart.
The bottom of the chart shows the nominal Usable Beam
Lengths.
2755-LD8
Usable Beam Length