SICK CLV 490, Руководство по эксплуатации

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Chapter 4 Operating Instructions
CLV 490 Bar Code Scanner
4-4
© SICK AG · Division Auto Ident · Germany · All rights reserved 8 008 796/0000/25-06-2002
Installation
4.2.7 Distance between the CLV and the bar code
Basic alignment between the CLV and the bar code
Depending on the application, the line scanner or line scanner with oscillating mirror versions
of the CLV is used. Fig. 4-4 shows how the device is aligned with the bar code on the object
for each of the two scanning methods.
Reading distance from the bar code and aperture angle
α
The distance between the reading window of the CLV and the bar code must not exceed
the technical limits. The height of the reading field is shown as a function of the reading
distance for various resolutions (module widths) depending on the CLV type in Chapter 10.2
Specification diagrams, Page 10-1 .
Fig. 4-5 shows the definition of the reading distance a from the reading window and of the
aperture angle
α
each of the two scanning methods.
The useful aperture angle is typically 56
°
for the line scanner and max. 50
°
for the line scan-
ner with oscillating mirror. Due to the V-principle of beam deflection, the reading field height
(for evaluating the useful length of the scan line) depends on the readling distance.
Fig. 4-4: Scanning methods: alignment with bar code and conveyor direction
Line scanner Line scanner with
oscillating mirror
Fig. 4-5: Definition of the reading distance a and of the aperture angle
α
α
105
°
α
Line scanner Line scanner with oscillating mirror
Reading distance a
Reading distance a