Rockwell Automation DeviceNet Communications Module - Manual (Page 50)

6-2 DeviceNet Communications Module
6.2 Understanding the I/O Image
The DeviceNet specification requires that the terms input and
output be defined from scanner’s point of view.
Output I/O is data that is output from the scanner and consumed by
the DeviceNet module.
Input I/O is status data that is produced by the module and
consumed as input by the scanner. The I/O image table will vary
based on the configuration of the Mode Jumper (J2) on the module
and DSI I/O Config (15). The image table always uses consecutive
words starting at word 0.
Figure 6.1 illustrates an example of a Single-Drive I/O image (6-bit
words).
Single-Drive mode is the typical configuration, where one node
consists of an MD65 drive with a DeviceNet module.
For Multi-Drive mode, where one node can consist of up to 5 drives,
refer to chapter 8, Using Multi-Drive Mode.
Figure 6.1 – Example of Single-Drive I/O Image
Controller Scanner Module MD65 Drives
DeviceNet MDI
Output
Image
(Write)
Input
Image
(Read)
Message
Handler
Message
Buffer
0 Logic Status
1 Feedback Logic Status
Feedback
Word and I/O
Message
Handler
0 Logic Command
1 Reference Logic Command
Reference