Operating Instructions
Chapter
6
CLV 490 Bar Code Scanner
8 009 993/O824/20-12-2004
©
SICK AG · Division Auto Ident · Germany · All rights reserved
6-29
Operation
Explanation
Internal object tracking
Internal object tracking can be used in autofocus mode with "Differential background and
tracking" mode or with event-controlled focus position switchover (e.g. by means of height-
control photoelectric switches at switching inputs "IN 0" to "IN 3"). If the reading pulse is
started via an external sensor, fast debouncing (
≤
5 ms) is used for the "Sensor" switching
input irrespective of the parameter settings. The CLV receives the signals from the
incremental encoder via switching input "IN 4". At a constant conveyor speed, the increment
can be triggered via an internal timer increment (100 Hz) (set the value for "Path per
increment encoder pulse" to 0), which means that an encoder does not need to be
connected to IN 4.
With object tracking, the reading field length corresponds to the distance in conveying
direction between the sensor for starting the reading pulse and the parameterized object
release point (see
). The focus release point is before the object release
point. The CLV uses the internal object management system and its object list to track the
objects passing through the reading field, whereby the distance measurement enables
objects to be detected and the corresponding focus positions in the focus list to be
assigned. The increment management system continuously locates the current position of
the objects in the reading field in the conveying direction. The focus list acts as a circular
buffer, whereby the oldest entry determines the current focus position. If the CLV calculates
that the end of an object being conveyed through the reading field has passed the
parameterized focus release point, the CLV switches to the next focus position and deletes
the object from the focus list. The reading result for an object is not output until the object
has left the object release point.
1. Parameterize internal object
tracking
–
contd.
–
Ö
D
EVICE
CONFIGURATION
tab
Ö
A
SSIGNMENT
OF
I
NPUTS
section
Ö
IN 4
– Conveyor increment
Note:
Connect external incremental encoder to "IN 4" switching input!
2. Define scanner position
referred to the reading field
Ö
D
EVICE
CONFIGURATION
tab
Ö
S
CANNER
P
OSITIONS
P
ARAMETERS
button
Ö
A
NGLES
section
– Angles: alpha, beta and gamma
Ö
C
OORDINATES
section
– x-, y- and z-coordinates
3. Teach-in background
(optional)
Ö
Menu CLV 490
Ö
D
EVICE
FUNCTIONS
Ö
Background
– Teach-in
Check taught-in background:
Ö
R
EADING
CONFIGURATION
tab
Ö
A
UTOFOCUS
section
– S
HOW
B
ACKGROUND
button
Display actual background profile:
Ö
Menu CLV 490
Ö
B
ACKGROUND
ANALYSIS
Action
Settings in CLV-Setup
Table 6-12: Guide: Parameterzing internal object tracking (contd.)