READING FEATURES
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7
7.2 LINEAR CODE READING
The number of scans performed on the code by the DS4800 and therefore the decoding
capability is influenced by the following parameters:
number of scans per second
code motion speed
label dimensions
scan direction with respect to code motion
At least 5 scans during the code passage should be allowed to ensure a successful read.
7.2.1 Step-Ladder
Mode
If scanning is perpendicular to the code motion direction (Figure 90), the number of effective
scans performed by the reader is given by the following formula:
SN = [(LH/LS) * SS] – 2
Where: SN = number of effective scans
LH = label height (in mm)
LS = label movement speed in (mm/s)
SS = number of scans per second
Figure 90 - "Step-Ladder" Scanning Mode
For example, the DS4800 (800 scans/sec.) for a 25 mm high code moving at 1250 mm/s
performs:
[(25/1250) * 800] - 2 = 14 effective scans.
Direction of code
movement at LS speed
Laser beam
DS4800
LH
