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XAC80 Profibus-DP
®
7.8 "Dead Zone"
The so-called "Red Zone" occurs when:
Number of revolutions =
Total resolution
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.
EXAMPLE
“XAC80 16/16384 PB...”: multiturn encoder

Hardware counts per revolution
= 65,536 (2 16 )

Hardware number of turns = 16,384 (2 14 )

Total hardware resolution
= 1 073 741 824 (2 30 )
Set parameter values:

Counts per revolution
= 50,000
 Number of revolutions = 8,000
 Total resolution
= 400 000 000
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