Appendices
A-6
MS-610 Scanner User’s Manual
A
p
p
e
ndice
s
Appendix C — Orientation
If the bar code label bars are parallel to the direction of travel, as shown in
figure A-3, the label is said to be in a
ladder
orientation; if the bars are per-
pendicular with the direction of travel, the label is said to be in a
picket fence
orientation (figure A-4).
Ladder Orientation
In general, depending on label
size and speed, ladder orien-
tation is preferable because
different portions of the label
are scanned as the label goes
by. In addition, label place-
ment is not as critical. As
shown in figure A-3, a label
can be successfully read if
fully placed (including quiet
zones) anywhere within the
readable portion of the scan
line.
Note:
Unless your application calls for a stop and go label, it is unlikely
that ladder orientation will be used with a raster scanner.
Picket Fence Orientation
Unlike ladder, picket fence
allows only a small portion of
the entire label to be scanned.
As a result, labels must be of
good quality since even slight
label imperfections such as
extraneous ink, voids, etc., can
cause misreads or non-reads.
One advantage of the picket fence over the ladder orientation is in the area
of label speed. In ladder mode, the label travel distance is the height of the
bar code; in picket fence mode, the label can be read while it travels the full
distance of the scan width.
Note
: Either ladder or picket fence can be rotated without losing its orien-
tation, provided that the label’s direction of travel does not change in rela-
tion to the scan line.
Figure A-3 Ladder Orientation
Scan line
(full width)
Direction of label travel
Label
Label
placement
area
Figure A-4 Picket Fence Orientation
Scan line
Label
placement
area
Direction of label travel
