Red Zone - Datalogic AMT58*-PN Series Instruction Manual

AMT58x-PN ProfiNET®

9.5 "Red Zone"

The so-called "Red Zone" problem occurs when the Number of
revolutions (i.e. the
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 overall set resolution
from the overall physical resolution of the device as many times as
until the difference is less than the overall set resolution. When the
encoder crosses the limit of the last value in the overall physical
resolution, a counting error occurs, i.e. a jump in the position count.
The problem is represented graphically in the following Figure.
EXAMPLE
HM58 16/16384 PT multiturn encoder
Physical resolution:
 Singleturn physical resolution
16
(2 )
 Multiturn physical resolution = 16384 revolutions = 14 bits (2
 Overall physical resolution
Set values:

Measuring units / Revolution

Total measuring range
power of 2
It results from this:
 Number of revolutions
This can be proved easily:
Overall physical resolution
Overall set resolution
66
Total measuring range
= 65536 counts/rev. = 16 bits
= 1073741824 = 30 bits (2
= 65536 = 2
= 442236928 = it is NOT a
= 6748 = it is NOT a power of 2
1073741824
=
442236928
/ Measuring units /
14
)
30
)
16
=
2,427...