C2R 30-005, User Manual

Page: 51 / 183

Colibri serie 6 : User’s guide
© 2000-2012 C2R Technologie, Sarl. All rights reserved
51
Rev. A
Thermal Considerations
Care must be taken when designing the Image Engine into any system. Internal heating of the
Image Engine can occur in high duty cycle scanning applications in several ways. The high
visibility aimer dissipates a significant amount of power as heat. The illumination and aiming
LEDs also release heat, and are a major contributor to thermal increases in high use or in
presentation mode.
An increase in temperature around an Image Engine can cause noise levels on the imager,
degrading image quality. The thermal rise can also affect the laser diode. In a continuous
scanning or high use environment, the Image Engine temperature can rise 15° to 20°C. Under
high ambient temperature conditions, the laser diode is at risk of thermal breakdown and
possible failure. The image quality and decode performance will also degrade
The Power Control PWM can be used to reduce the effect of the illumination LEDs on thermal
rise, however, this also reduces the intensity of the illumination. Reducing the intensity of the
illumination reduces total power used but can also reduce the depth of field in low light
environments.
Centering
Use Centering to narrow the scanner’s field of view to make sure the scanner reads only those
bar codes intended by the user. For instance, if multiple codes are placed closely together,
centering will insure that only the desired codes are read. (Centering can be used in
conjunction with Aimer Delay, for the most error-free operation in applications where multiple
codes are spaced closely together. Using the Aimer Delay and Centering features, the scanner
can emulate the operation of older systems, such as linear laser bar code scanners.) In the
example below, the gray area is the full scanner field of view and the white area is the
centering window. Bar Code 1 will not be read, while Bar Code 2 will be
.