Rockwell Automation 20-COMM-D DeviceNet Adapter Series B FRN 2.xxx - Manual (Page 86)

5-2 Using the I/O
20-COMM-D DeviceNet Adapter User Manual
Publication 20COMM-UM002G-EN-P
Understanding the I/O Image The terms ‘input’ and ‘output’ are defined from the controller’s point of
view. Therefore, output I/O is data that is produced by the controller and
consumed by the adapter. Input I/O is status data that is produced by the
adapter and consumed as input by the controller. The I/O image will vary
based on the following:
• Size (either 16-bit or 32-bit) of the Reference/Feedback words and
Datalink words used by the drive. To determine the size of the
Reference/Feedback and Datalinks, view adapter Parameters 07 - [Ref/
Fdbk Size] and 08 - [Datalink Size]. For information to access
parameters, see
Using the PowerFlex 7-Class HIM to Access
Parameters on page 3-2 .
• Configuration of I/O (Parameter 13 - [DPI I/O Cfg]). If all I/O is not
enabled, the image is truncated. The image always uses consecutive
words starting at word 0.
ControlLogix Controller Image
Controller tag names for the I/O image may vary based on the drive being
used and whether the DeviceNet Tag Generator software tool was used to
replace the generic (non-descriptive) names with descriptive names.
The ControlLogix controller I/O image changes depending on the size of
the drive’s Reference/Feedback and Datalinks, and the number of Datalinks
used.
Table 5.A , Table 5.B , and Table 5.C show the I/O image when using
various PowerFlex 7-Class drives, and all Datalinks enabled.
TIP: The ControlLogix controller’s 1756-DNB scanner is a DWORD
(double word) device. The following tables show the I/O as 32-bit words.
For example, if 4 bytes, 2 words, or one DWORD is consumed, then the
lower 16 bits of the output (Least Significant Word) is the Logic Command
word and the upper 16 bits (Most Significant Word) is the speed Reference.
For the input, the lower 16 bits (LSW) is the Logic Status word and the
upper 16 bits (MSW) is the speed Feedback.