Chapter
10
Operating Instructions
CLV 490 Bar Code Scanner
10-38
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SICK AG · Division Auto Ident · Germany · All rights reserved
8 008 796/0000/25-06-2002
Appendix
10.4
Optional heating
10.4.1
Features
•
Integrated heater (permanently installed)
•
Wider range of applications for CLV: up to max. –35
°
C
•
Supply voltage 24 V DC +20 %/–10 %
•
CLV enabled via internal temperature switch (power-up delay approx. 35 ... 40 min. at
24 V DC and min. ambient temperature of –35
°
C)
•
Required cable cross-section (power supply): min. 0.75 mm
2
10.4.2
Design
The heating system comprises two parts:
•
the front window heater
•
the housing heater
The optional heating system is installed and tested at the factory. The user cannot install it
on site.
10.4.3
Function
When the 24 V DC supply voltage is applied, a temperature switch first supplies electric
current to the heater only. This switch enables the supply voltage for the CLV when the in-
ternal temperature rises above 7
°
C during the warm-up phase (approx. 35 min). The device
then performs a self-test and switches to Reading mode. The "Device Ready" LED lights up
to indicate that the device is ready.
When the internal temperature has reached approx. 25
°
C, a further temperature switch
deactivates the housing heater and reactivates it if necessary. Reading mode is not inter-
rupted as a result. The front window heater remains active constantly. The temperature cur-
ve inside the housing is shown in
.
Fig. 10-35: CLV with heater: temperature curve inside the housing
Temperature
inside housing
[
°
C]
The temperature enables the operating
voltage for the CLV internally
Time [min]
