Datalogic AMT58 Series Manual page 433

AMT58x-PB Profibus®
6.9 "Red Zone"
The so-called "Red Zone" occurs when:
Total resolution
Number of revolutions =
Counts per revolution
is not a power of 2.
When this problem arises, the device must operate within the "red
zone" for a certain number of positions. The size of the "red zone" is
variable. To calculate it we must subtract the Total resolution value
from the Hardware total resolution of the device as many times as
until the difference is less than the the set Total resolution value.
When the encoder crosses the limit of the last Total resolution
section thus entering the "red zone", a counting error occurs, i.e. a
jump in the position count. The problem can be represented
graphically in the Figure below.
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