Transition Counter

Transition Counter is an integral part of the AGC system. Transition Counter determines the number of black bars that will be counted before an AGC sample is taken. Setting a Transition Counter value lower than the default of 14 gives the scanner less integration time for the candidate symbol, and makes the scanner more susceptible to false objects.

A Transition Counter value greater than 14 requires more bars to be present for the symbol even to qualify as an object. When setting the Transition Counter value, it is important to keep in mind what occurs when the symbol is first presented to the scanner-before gain is applied to the symbol. A few bars are usually missed due to distortion at first. Setting Transition Counter to the same value as the number of bars contained in the symbol can cause the scanner not to take an AGC sample at all. The value of 14 is optimal except in the case of low bar count due to:

• Symbols that are tilted so that only 10 bars or fewer are available in a single scan line. (See Symbol Reconstruction).

• Symbologies with typically low bar counts, such as Pharmacode. Applications using symbols with fewer than 10 bars should use Fixed Gain operation.