Scanning Considerations; Scanning Bar Codes - Symbol MC9090-G RFID User Manual Supplement

Scanning Considerations

Typically, scanning is a simple matter of aim, scan/decode and a few quick trial efforts master it. However, two
important considerations can be used to optimize any scanning performance:
Range
•
Any scanning device decodes well over a particular working range — minimum and maximum distances
from the bar code. This range varies according to bar code density and scanning device optics.
Scanning within range brings quick and constant decodes; scanning too close or too far away prevents
decodes. Move the scanner closer and further away to find the right working range for the bar codes being
scanned. However, the situation is complicated by the availability of various integrated scanning modules.
The best way to specify the appropriate working range per bar code density is through a chart called a
decode zone for each scan module. A decode zone simply plots working range as a function of minimum
element widths of bar code symbols.
Angle
•
Scanning angle is important for promoting quick decodes. Do not scan at too sharp an angle; the scanner
needs to collect the image to make a successful decode. Practice quickly shows what tolerances work.
NOTE Contact the Symbol Support Center if chronic scanning difficulties develop. Decoding of properly printed
bar codes should be quick and effortless.

Scanning Bar Codes

Ensure that a scan enabled application is loaded on the mobile computer.
1.
Aim the scan exit window at the bar code.
2.
Pull the trigger.
3.
Place the bar code in any orientation within the aiming pattern. Ensure the entire symbol is within the
•
rectangular area formed by the brackets in the aiming pattern. The red laser aiming pattern turns on to
assist in aiming. If necessary, the mobile computer turns on its red LED to illuminate the target bar code.
The green scan LED lights and an audible beep sounds, by default, to indicate the bar code was
decoded successfully. Note that when the mobile computer is in Pick List Mode, the bar code is not
decoded until the crosshair is touching the bar code.
Linear bar code
Bar Code Centered in Aiming Pattern
Figure 2-16
PDF417 symbol
Symbol
View Finder
(Aiming Pattern)
Operating the MC9090-G RFID 2 - 15