Fig. 10-23: Line scanner with oscillating mirror: Calculating the number of scans for fence-type bar
Line scanner with oscillating mirror: Lateral reading at object
Calculation for
standard decoder!
Specified values:
Number of scans n = ?
Transporting speed v = 0.5 m/s
Code length with idle zone l
C
= 100 mm
Code length under 10
°
:
Reading area height l
LH
= 500 mm
Scanning frequency f = 600 Hz
Bar code 100 % readable, all scans on the code
Codefenster s = 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
(approximation):
2. Required oscillating mirror
frequency: