Motorola SYMBOL MINISCAN MSXX04 - Manual (Page 33)

Installation 2 - 9
where:
D = Distance (in inches) from the front edge of the host housing to the bar code.
d = The host housing’s internal optical path from the edge of the housing to the front of the MiniScan scanner.
B = Internal optical path from the scan mirror to the front edge of the MiniScan scanner.
A = Scan angle in degrees.
Calculating the Usable Scan Length Method (Symbol MS954 Only)
Calculate usable scan length as follows (see Figure 2-9 on page 2-9 ):
L = 2.0 x (D+d+B) x Tan (A/2)
where:
D = Distance (in inches) from the front edge of the host housing to the bar code.
d = The host housing’s internal optical path from the edge of the housing to the front of the MiniScan scanner.
B = Internal optical path from the scan mirror to the front edge of the MiniScan scanner.
A = Scan angle in degrees.
Figure 2-9 Usable Scan Length Diagram
NOTE Usable scan length is determined by this formula, or 90% of scan line at any working distance. This
formula is based on good quality symbols in the center of the working range and length of bar code.
Table 2-2 Symbol MS954 Calculation Constants
Constants B A
MS954 0.87 47°
MS954 (Narrow Mode) 0.87 35°
NOTE The Symbol MS954 does not require margin on either side of the bar code to decode. The 47° scan line
provides identical scanning performance to older minscan devices (e.g., Symbol MS923) with a scan line
of 53°.
Consider the width of the scan line at any given distance when designing a system.
MiniScan
Host System
d D
A
Bar
Code
B
1/2 L
1/2 L
L