Rockwell Automation RECOMM-ENET EtherNet/IP Communications Module - Manual (Page 64)

6-6 EtherNet/IP Communications Module
6.4 Using Reference/Feedback
When enabled, Reference/Feedback begins at word 1 (16-bit) or
word 2 (32-bit) in the I/O image. The
reference (16 bits or 32 bits) is
produced by the controller and consumed by the adapter. The
feedback (16 bits or 32 bits) is produced by the adapter and
consumed by the controller. The size of the Reference/Feedback is
determined by the drive and displayed in Ref/Fdbk Size (18) in the
adapter.
The Reference value is a scaled value; it is not an engineering
value. For example, in Reliance Electric drives, the Reference is
scaled based on the value of Maximum Freq (55) where “32,767”
equals the Maximum frequency value, and “0” equals 0 Hz. Note
that the commanded maximum speed can never exceed the value
of Maximum Speed (82). The below table shows example
references and their results on a drive that has its Maximum Freq
(55) set to 130 Hz and Maximum Speed (82) set to 60 Hz.
For Reference/Feedback details about other DPI Hosts, refer to
their respective User Manuals.
Size Valid Values In I/O Image
16-bit -32768 to 32767 Word 1
32-bit -2147483648 to 2147483647 Word 2 and Word
3
Reference
Value
Scale Output
Speed
Feedback
Value Percent Value
32767 1 100% 130 Hz 60 Hz 2 15123 3
16384 50% 65 Hz 60 Hz 2 15123 3
8192 25% 32.5 Hz 32.5 Hz 8192
0 0% 0 Hz 0 Hz 0
1. A value of 32767 is equivalent to the Parameter 55 frequency value. The effects of values
greater than 32767 depend on whether the DPI product uses a bipolar or unipolar
direction mode. Refer to the documentation for your DPI product.
2. The drive runs at 60 Hz instead of 130 Hz or 65 Hz because Parameter 82 - [Maximum
Speed] sets 60 Hz as the maximum speed.
3. The Feedback value is also scaled based on the value of Parameter 55 - [Maximum
Freq], For example, 60/130 = 0.46 so 32767 x 0.46 = 15123.