Rockwell Automation 2755 Atomscan Bar Code Scanner - Manual (Page 18)

Chapter 3
Designing the System
3–7
Figure 3.5
Correct Setup of Scanner
20 _-30_
20 _-30_
Scanner between 20 _ and 30_
above or below the symbol
When using “A” range scanners to read symbols with high paper noise,
increasing the skew to 30
°
may enhance performance.
To select the correct AtomScan scanner for your application, you must
measure:
•
the distance between the scanner and the symbol (which must be within
the Read Range)
•
the apparent Narrow Element width. This equals the actual measured
Narrow Element width if the symbol is not pitched. See the section later
in this chapter, Compensating for Pitched Symbols.
•
the bar code symbol’s length and height (see Figure 3.1)
•
the speed at which the symbol will be travelling
Selecting the Correct
AtomScan Scanner