Microscan MS-820 User Manual page 70

Automatic Gain Control (AGC)
Important: AGC settings apply to both AGC gain control and symbol detection.
AGC Sampling Mode
Usage: AGC Sampling allows you to specify how automatic gain control sam-
pling will be done.
Definition: AGC is the acronym for Automatic Gain Control. AGC increases the depth
of field by attempting to maintain signal strength at a constant level
regardless of the range of the bar code symbol.
Serial Cmd: <KDgain,AGC sampling,AGC min,AGC max>
Default: Continuous
Options: 0 = Disabled
Disabled
Definition: When AGC Sampling is set to Disabled, gain levels can only be manu-
ally controlled by the Gain command.
Usage: Disabled is not recommended, but can be useful in certain applications
in which symbols do not require a large depth of field.
Leading Edge
Usage: Leading Edge is rarely used, but in some cases can improve scan rates
when symbols are skewed and the leading edge of a symbol is difficult to
locate.
Definition: Finds the leading edge of a symbol by looking for a 40 µS quiet zone fol-
lowed by the number of transitions, stores the highest value of the sam-
ples, and adjusts the AGC accordingly at the end of the scan.
Continuous
Usage: Continuous is the default and the preferred mode for sampling analog
signal amplitude.
Definition: Samples AGC throughout the scan at the rate averages the sample val-
ues, and adjusts the AGC value at the end of the scan.
MS-820 Industrial Bar Code Scanner User's Manual
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Chapter 4 Read Cycle
1 = Leading Edge 2 = Continuous
4-17