44
BCL 558
i
Leuze electronic
5.5
Reading field curves / optical data
Bar code characteristics
Notice!
Please note that the size of the bar code module influences the maximum reading distance
and the width of the reading field. Therefore, when selecting a mounting location and/or the
bar code label, take into account the different reading characteristics of the scanner with
various bar code modules.
Figure 5.4:
The most important characteristics of a bar code
The range in which the bar code can be read by the BCL 558
i
(the so-called reading field)
depends on the quality of the printed bar code and its dimensions.
Therefore, above all, the module of a bar code is decisive for the size of the reading field.
Notice!
A rule of thumb: The smaller the module of the bar code is, the smaller the maximum reading
distance and reading field width will be.
M
=
Module: The narrowest line or space of a bar code in mm
Z
B
=
Wide element: Wide lines and spaces are a multiple (ratio) of the
module.
Module x Ratio = Z
B
(Normal Ratio 1 : 2.5)
B
Z
=
Quiet zone: The quiet zone should be at least 10 times the
module, but not less than 2.5mm.
L
=
Code length: The length of the bar code in mm including the start
and stop characters. The quiet zone is included depending on the
code definition.
S
L
=
Bar length: Height of the elements in mm