Lika DRAW WIRE SFA-10000 Series, User Manual

Page: 66 / 72

SFA-5000 • SFA-10000 Profibus
6.9 "Red Zone"
The so-called "Red Zone" occurs when
Total resolution
or
Counts per
revolution are 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
SFA-xxxxxx-8192-xxx draw-wire encoder

Hardware counts per revolution = 8,192 (2 13 )

Hardware number of turns
= 4,096 (2 12 )

Total hardware resolution = 33,554,432 (2 25 )
Set parameters values:
 Counts per revolution
= 8,192

Number of revolutions
= 2,000
 Total resolution
= 16,384,000
MAN SFA_5000_10000_PB E 1.0 Profibus® interface 66 of 72