Figure 3.6 read range vs. narrow element width – Rockwell Automation 2755 Atomscan Bar Code Scanner User Manual
Page 20
Chapter 3
Designing the System
3–9
Table 3.A and Table 3.B show the relationship among the symbol density
(width of the narrowest bar or space), the Read Range, and the usable scan
width. The performance may vary slightly for raster units.
Figure 3.6 gives the same information as Table 3.A in graphic form.
Figure 3.6
Read Range vs. Narrow Element Width
5
10
.25
15
20
.50
25
30
.75
35
40
1.00
45
50
1.25
5
12.5
10
25.4
Apparent Minimum Element W
idth
Inches
Centimeters
Read Range
(from scan window)
1
0
2
3
4
6
7
8
9
“A”
“B”
Mils
(.001 in.)
mm
0
0
0
5.0
2.5
7.5
10.0
15.0
17.5
20.0
22.5
Read rates will vary due to differences in symbol quality and positioning. For
optimum performance with your application:
1. Configure the decoder for Decode Mode = Continuous. See the Enhanced
Decoder user’s manual (Publication No. 2755-833). The section in
Chapter 14 titled Display Status and Counters has a discussion of the
“decoder performance indicator” (decoder performance = read rate).
2. Map out a symbol placement area by manually moving your symbol
in and out, back and forth, while observing decoder performance on the
screen.