Rockwell Automation 2755 High Performance VLD Scanner - Manual (Page 21)

3–8 Installation Considerations
The LD8 scanners can read bar code labels at various distances
depending on the apparent minimum element width
① and scanner to
label pitch. The scanner can read labels within one of three read
ranges: A, B, or C.
Figure 3.8 shows the reading distances for each range of the LD8
scanner. Table 3.B lists the read ranges for the LD8 scanners in
numeric format.
Refer to ”Compensating for Pitched Symbols” if your labels are
pitched.
Figure 3.8
Read Range vs Apparent Minimum Element Width (LD8 Scanners)
➁
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
➂
➀
For minimum element width, refer to ”Determining Apparent Minimum Element Width” in Chapter 3.
➁
1 mil = 0.001 inches ➂
Read ranges based on four character, Code 39 labels with a wide to narrow bar ratio of 2.6 to 1 and
a print contrast ratio of .75 or better. Read ranges will vary with bar code symbol quality.
➀
2755-LD8 Read Ranges