Microscan MS-850 User Manual page 125

Single Scan Line Picket Fence Calculation
For single scan line picket fence scanning (Top Offset) setting equal to Bottom
Offset), use the following formula:
( )
SW LL –
 
--------------------------- ×
DR – 3 = number of complete decodes
 
LS
SW (Scan Width) (picket fence formula only) is the width
across the scan beam, at a given distance from the
scanner, in which a label can be read.
LL (Label Length) (picket fence formula only) is the length
of the longest printed label to be read plus the length
of the quiet zones.
LS (Label Speed) is the distance per second that a symbol
moves through the scan.
DR (Decode Rate) is the number of decodes per second
that a given symbol receives (as derived from a sta-
tionary scan test).
Example:
LL = 2 inches (including quiet zones)
LS = 100 inches per second
SW = 4 inches
DR = 1000 decodes per second
( )
4 2 –
 
----------------
× 1000 – 3 = 17 complete decodes
 
100
Angled Picket Fence Calculation
The number of complete scans for angled picket
fence is calculated the same as that for picket
fence, with the exception that the scan width is
shortened in proportion to scan tilt.
: While the formulas given here solve for
Note
the predicted number of decodes, you may also
use the formulas to solve for other parameters
that might be changed, such as label speed,
label length, etc.
MS-850 Raster Scanner User's Manual
Formulas for Number of Decodes
1
Direction of label travel
Scan Line
Direction of label travel
Scan Line
A-13