Motorola MC3000, Руководство пользователя

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Operating the MC3000 2 - 27
Scan LED Indicators
The red/green Scan LED Indicators (located in the Indicator LED Bar and in the rotating turret) indicates the scan
status. For the location of the Scan LED Indicators see,
Figure 1-1 on page 1-3
.
Scanning Considerations
Scanning consists of; aim, scan and decode. Scanning performance can be optimized by considering the range
and the scanning angle:
•
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
The scan angle is important for optimizing decode performance. 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 do not 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.
Laser Decode Ranges
The decode ranges provide the decode ranges for barcodes of specified densities.
Figure 2-28
shows the laser
decode ranges and
Table 2-10 on page 2-28
lists the scan ranges for the selected bar code densities. The
minimum element width (or “symbol density”) is the width in mils of the narrowest element (bar or space) in the
symbol. The maximum usable length of a symbol at any given range is shown below.
Table 2-9
Scan LED Indicators
LED Status Indication
Off Not scanning.
Solid Red Laser enabled, scanning in process.
Solid Green Successful decode.
NOTE
Contact the Motorola Enterprise Mobility Support Center if chronic scanning difficulties develop. Decoding of
properly printed bar codes should be quick and effortless.