Rockwell Automation 1761-NET-DNI DeviceNet Interface (DNI) - Manual (Page 18)

Publication 1761-UM005B-EN-P - October 2006
18 Operation
Input Image
The input image is a configurable array of 16-bit data words. The
image is configurable from 1…16 data words for DNI Series A (1…32
data words for DNI Series B). The actual data that resides in the input
image is delivered to the DeviceNet master by one of three
mechanisms.
• Polled: Where the DeviceNet Master sends a poll request with
output data and the DNI responds with its current input data.
• COS (Change of State): Where the DNI detects that data has
changed within the input image and automatically sends the
data to the DeviceNet Master.
• Cyclic: The DNI continuously sends the input image data to the
master at a user/scanner-defined time interval, regardless of
whether the data has changed.
Output Image
The output image is a configurable array of 16-bit data words. The
image is configurable from 1…16 data words for DNI Series A (1…32
data words for DNI Series B). The actual data that resides in the
output image is delivered to the DNI from the master by one of two
mechanisms:
• Polled: Where the DeviceNet Master sends a poll request with
output data and the DNI responds with its current input data.
• COS (Change Of State): Where the DeviceNet Master detects that
data has changed within its output image and automatically
sends the data to the DNI.
• Cyclic: The DNI continuously receives the output image data
from the master at a user/scanner-defined time interval,
regardless of whether the data has changed.
Network Configuration
Software All DNI I/O parameters are configured with software such as the DNI
Configuration Utility, RSNetWorx, or DeviceNet Manager and stored as
part of the network configuration.
Configuration software is covered in Setup, Programming, and
Troubleshooting on page 53.
Individual settings of the DNI are covered in DNI Configuration
Parameters and Programming Notes on page 27.