Argox AS-9500 - Manual (Page 42)

41
Thermal and Centering
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 Auto-sense
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 imager’s field of view to make sure
the imager 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
imager can emulate the operation of older systems, such as linear
laser bar code imagers. In the example below, the gray area is the
full imager field of view and the white area is the centering
window. Bar Code 1 will not be read, while Bar Code 2 will be.