Rockwell Automation 2755 AdaptaScan Bar Code Readers - Manual (Page 35)

Installation Considerations 2–9
Use the following formulas to calculate the number of scans per
label and the minimum number of scans per second needed for an
application. The minimum scan speed required is based on five
scans per label.
Picket Fence Orientation Step Ladder Orientation
Formulas
Scans per Label =
Minimum Scan
Speed Required =
(X-Y)
Z
A
A x H
Z
Z x 5
H
Z 5
X-Y
x
Where:
A = Derated Scan Rate (Nominal Scan Rate –5%)
= 285 SPS for Catalog No. 2755-SN3 Readers
= 475 SPS for Catalog No. 2755-SN5 Readers
= 760 SPS for Catalog No. 2755-SN8 Readers
H = Height of bars in bar code. In inches
①
.
X = Usable beam length at minimum read distance. In inches
①
.
Y = Bar code length including quiet zones. Typically in inches
①
.
Z = Label speed. In inches per second ① .
MINIMUM SCANS PER LABEL MUST BE
u = 5.
① You can use other units of measure, such as meters, as long as all
measurements use the same unit.
Calculating
Scans per Label