Rockwell Automation 2755-L7, -L9 Scanners - Manual (Page 18)

Chapter 3
Installation Considerations
3–5
Figure 3.7 shows the size and shape of the scanning window. The black area
is a no read are area.
The Usable Beam Length (bottom of chart) is compared to the the Reading
Distance (top of chart). The Usable Beam Length is slightly less than the
projected beam length. The reading distance is measured from the scan
window to the center of the symbol.
Figure 7
Usable Beam Length
To estimate the Usable Beam
Width:
1. Determine the distance from
the face of the scanner to the
center of the bar code symbol.
This distance is your Reading
Distance.
2. Locate your Reading
Distance on the L7 or L9
diagram (the Reading
Distances are displayed across
the top of each scale).
3. Displayed across the bottom
of each scale are the nominal
Usable Beam Lengths.
L7 Reading Distance ①
Inches
Centimeters
Usable
Beam
Length
Reading Distance
40
101.6
45
114.3
5
12.7
10
25.4
15
38.1
20
50.8
25
63.5
30
76.2
35
88.9
50
127.0
0
0
29.6
75.2 33.0
83.8 26.1
66.3 36.5
92.7 5.2
13.2
8.7
22.1
12.2
31.0 15.6
39.6 19.1
48.5 22.6
57.4 NA
NA
Usable Beam Length (nominal)
Inches
Centimeters
L9 Reading Distance ①
Reading Distance
5
12.7
10
25.4
15
38.1
20
50.8
25
63.5
30
76.2
0
0
2.9
7.4 4.8
12.2
6.7
17.0
8.6
21.8
10.6
26.9 12.5
31.8 NA
NA
Inches
Centimeters
Usable Beam Length (nominal)
Inches
Centimeters
Usable
Beam
Length
① Measured from the face of the scanner to the center of bar code symbol.
Usable Beam Length