Rockwell Automation 2090 Ultra3000 Servo Drives Integration Manual - Manual (Page 139)

Publication 2098-IN005C-EN-P — March 2008
Understanding Motor Feedback Signals and Outputs 139
High Resolution Encoder
Outputs When the incoming encoder feedback on CN2 is a high resolution
(SIN/COS) signal, the drive is capable of generating more than just 4
counts/cycle (as with incremental encoders). The Ultra3000 drive is
capable of breaking the SIN/COS encoder signals into as many as
1024 counts/cycle. For example, a 1024 cycle/rev SIN/COS encoder
can result in 1024 x 1024 (high resolution) counts/rev.
Absolute High Resolution Encoder Signals
The high resolution buffered outputs (listed below) are available from
the drive (CN1-16 through CN1-21) and software selectable.
•
Buffered Outputs are conditioned SIN/COS signals resulting in a
square wave (A quad B) signal (refer to ). This signal will have the
same number of cycles/rev as the incoming SIN/COS encoder
signals found on CN2.
•
Interpolated Outputs are square wave (A quad B) signals
reflecting the interpolation value chosen in software. The
minimum interpolation value allowed is x4, which gives the same
output as selecting buffered (as described above).
•
Divided Outputs are the result of a divisor (selected in software)
and an interpolation value (also selected in software). For
example, with an interpolation value of x8 and a divisor of 2, the
CN1 buffered output will be the (x4) square wave representation
of the original incoming SIN/COS signal from CN2.
One
Cycle
Voltage
Time
CN1-10 (SIN/AM+) Unbuffered encoder feedback signal to drive, 1024 cycles/rev.
CN1-12 (COS/BM+) Unbuffered encoder feedback signal to drive, 1024 cycles/rev.
CN1-16 (SIN/AMOUT+) Buffered output from drive
CN1-18 (COS/BMOUT+) Buffered output from drive
1
2
3
4
1
2
3
4
Voltage
IMPORTANT
The interpolation value selected in software is what the drive
uses internally to close the feedback loops regardless of any
divisor value chosen to condition the signals present on CN1.