Fig. 10-41: Line scanner with oscillating mirror: calculating the number of scans for fence-type bar
Line scanner with oscillating mirror: side read on object
Calculation for
standard decoder!
Specified values:
Number of scans n = ?
Conveyer velocity v = 0.5 m/s
Code length with blanc zone l
C
= 100 mm
Code length under 10
°
:
Reading field height l
LH
= 500 mm
Scanning frequency f = 600 Hz
Bar code 100 % readable, all scans on the code
Code windows = l
LH
- l
C
1. Dwell time of the bar code
in the reading area:
l
CW
100 mm
cos 10
----------------------------- 102 mm==
t
s
v
---=
t
l
LH
l
CW
–()
v
-----------------------------=
t
0.5 0.102
–()
0.5 m/s
----------------------------------------=
t = 796 ms
f
SW
1
t
----=
f
SW
1
0.796 s
-----------------------=
n
600 Hz
1.26 Hz
----------------------=
n
f
f
SW
----------=
f
SW
= 1.26 Hz
n = 476
3. Number of possible scans
(rough estimate):
2. Required oscillating mirror
frequency:
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