LD25x
8.4.2 “Round-Loop” function
This operational mode is often used with rotating round tables or similar
applications, where the absolute encoder information is only used for a limited
and repeating range of the encoder (as for instance one revolution of the table,
which does not necessarily result in one revolution of the encoder shaft). The
“Round-Loop” function never uses any negative display value.
The “Round-Loop” function allows a programmable number of encoder steps to
be assigned to one complete 360º rotation of the table. To avoid miscounting
when passing the mechanical overflow of the encoder range, the total encoder
resolution should be an integer multiple of the number of steps for one loop.
To proceed with set-up operation, please first proceed as explained in section
“8.4.1 Normal SSI display” on page 30.
Then set the “Round-Loop” register (
r-LooP
item) to the number of steps
corresponding to one revolution of the table. You are free to scale the display to
any engineering units desired, by setting the scaling factors correspondingly.
If you like to scale your display with the angular display format 359º59’, just
change the “Display” register (
diSPLA
item) from “0” to “359,59”. This will also
automatically disable the general scaling factors.
The subsequent diagram shows the “Round-Loop” function with a 13-bit
encoder, assuming that one table revolution corresponds to 2048 encoder steps
and the zero position is set to “1024”.
8192
2048
r-LooP = 2048
0-PoS = 1024
0
360
180
degrees
1024
Original encoder signal
Round-Loop display
Encoder 13Bit
Direction = 0
0-Position = 1024
r-Loop = 2048
“Round-Loop” operation with 2048 steps / revolution when using a 13-bit
encoder
MAN LD25x E 1.0.odt
Hints for application
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