Scanning Options - Symbol PDT 7200 Series Product Reference Manual

PDT 7200 Series Product Reference Guide
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. So you need to find the right working range for the bar codes you
are scanning. However, the situation is complicated by the availability of multiple integrated
scanning modules, some with specialized capabilities such as long range and 2-D decode
capability. The best way to specify 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. See
Appendix A, Specifications
terminal.
Angle
Scanning angle is important for promoting quick decodes. When laser beams reflect
directly back into the scanner from the bar code, this specular reflection can "blind" the
scanner.
To avoid this, scan the bar code so that the beam does not bounce directly back. But don't
scan at too sharp an angle; the scanner needs to collect scattered reflections from the scan
to make a successful decode. Practice quickly shows what tolerances to work within.
Note: Contact the Symbol Support Center if you have chronic difficulties
scanning. Decoding properly printed bar codes should be quick and
effortless.

Scanning Options

Smart Raster Capability
All integrated 1-D/PDF417 scan elements may be programmed for "Smart Raster"
capability, which causes the scanner to emit a raster pattern dynamically optimized to the
particular PDF417 bar code's shape. To increase scanning efficiency and optimize decode
time, the scanner determines the geometry of the bar code and opens at a rate and size
optimal for decoding that bar code.
In normal "Smart Raster" operation, a trigger pull causes a slab raster pattern to appear. If
the target is a 1-D bar code, the pattern never gets beyond a slab raster. But if the target
4-8
for more information about the decode zone for the PDT 7200