Microscan N2210WZ Owner's Manual page 129

When To Use Fixed Gain vs. AGC
The AGC settings
as they provide the best overall scannable area. However, there are times when AGC will
have difficulty locking onto the symbol of interest, especially when extraneous non-symbol
objects in the field of view appear to be symbols. AGC can only base its measurements on
one object. If that object is not the actual symbol, AGC performance and consistency are
adversely affected.
Leading Edge bases its calculations on the first object it detects, even if the first object is
not a symbol. This is helpful if the symbol is always at the leading edge of the decode direction.
Continuous is the recommended setting for Microscan scanners. Continuous always
samples throughout the entire scan but is most interested in the object with the most
sharply-defined bars. This can occasionally mislead the scanner when bar-like objects or
specular reflection enter the field of view.
Fixed Gain is preferable if AGC repeatedly fails to choose the correct
for the application. In some applications, symbols might be surrounded by a greater number
of symbol-like false candidates than actual symbols. The Fixed Gain setting will never
change its value, so once it is set, surrounding objects in the field of view will not distract
the scanner from decoding actual symbols.
Fixed Gain is also useful in applications using symbols that have very low bar counts, or in
applications using
The AGC Minimum
of field limitations that are not conducive to Fixed Gain operation.
To determine the appropriate minimum and maximum gain:
• Set AGC Sampling Mode
that yields successful decodes in the application (both the lowest and the highest gain
levels).
• Enter those values in the AGC Minimum and AGC Maximum fields. This will leave the
scanner room for gain changes to increase depth of field (within the limitations of what
works for the application).
Maximum gain may be too high for symbols on white backgrounds, because it may
attempt to process false bars. Especially in applications using symbologies that require
more processing, setting gain too high can slow decode performance substantially.
Setting a minimum gain can prevent the system from occasionally "under-gaining"
because of previous false candidates that appear very bright.
QX-870 Industrial Raster Scanner User's Manual
(Leading Edge or Continuous) are preferable for most applications,
Symbol Reconstruction
and AGC Maximum
to Disabled (Fixed Gain)
on symbols with tilted or skewed placement.
parameters are useful in applications with depth
and find the range of gain levels
Scanner Parameters
Gain Level setting
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