Operating Instructions
Chapter
3
CLV 490 Bar Code Scanner
8 008 796/0000/25-06-2002
©
SICK AG · Division Auto Ident · Germany · All rights reserved
3-5
Product description
3.2
Method of operation
The CLV first scans the bar code with a scan line and then decodes it. The data is forwarded
via the main data interface (serial host interface) to a host/PC for further processing. An
overview of the CLV functions is provided in
.
The CLV is equipped with two decoders:
•
The SMART decoder (
S
ICK
M
odular
A
dvanced
R
ecognition
T
echnology) for decoding
bar codes with small code height, bar codes that are dirty or damaged, as well as bar
codes that are tilted excessively (azimuth angle)
•
The tried-and-tested standard decoder of the CLV series
The CLV derives useful diagnosis data from the reading process and can transfer it to also
the host. It also records operating data that can be interrogated at any time. The quality of
the read can be checked in percentage evaluation mode.
To start the reading process when an object is located in the reading field, the CLV requires
a suitable trigger. This opens an internal time window ("reading interval") in the CLV. In the
default configuration, this trigger is supplied by an external reading pulse sensor. Alternative
trigger sources include Free-running mode or a command via the host interface (for more
complex applications: OTC trigger).
The current operating status is indicated by four LEDs.
If the trigger is supplied externally, the "Sensor" switching input instructs the CLV to start the
reading process. The five "IN 0 ... IN 4" switching inputs switch the focus position in
response to certain events, as an alternative to the autofocus function. The "IN 3" and
"IN 4” inputs can also be assigned special functions. The four "Result 1 ... Result 4" swit-
ching outputs can be assigned to different functions for displaying the result status and also
control external devices, such as a PLC.
The CLV is operated and configured via the auxiliary interface (serial terminal interface) using
the "CLV-Setup" software or via the host interface/terminal interface using command
strings.
System, warning, and error messages help you to configure the device and to locate the
source of errors during startup and reading mode.
Fig. 3-2:
Block diagram: CLV functions
"Sensor"
"IN 0"
"IN 1"
"IN 2"
"IN 3"
"IN 4"
"Result 1"
"Host"
"Terminal"
"Result 2"
"Result 3"
"Result 4"
Scanner
Decoder
Interface
V
S
Photoelectric
switch
Reading pulse
Signal
1)
Focal control
Trigger One-Shot
Conveyer increment
1) if required
PC
Operation
Parameterization,
etc.
HOST
Further processing
of the reading result
Status display
e. g. Device Ready
e. g. Good Read
e. g. No Read
e. g. Match 1
CLV 490