Rockwell Automation 1793-OE2S FLEX INTEGRA ANALOG MOD - Manual (Page 53)

Publication 1793-6.5.1 - April 1999
6-2 Input, Status, Output and Configuration Files using ControlNet
Scheduled Data-Transfer
Scheduled data transfer:
• is continuous.
• is asynchronous to the controller program scan.
• occurs at the actual rate displayed in the Actual Packet Interval field on
the programming software ControlNet I/O mapping (monitor) screen
Unscheduled Data-Transfer
Unscheduled operations include:
• unscheduled non-discrete I/O data transfers–through ControlNet I/O
Transfer (CIO) instructions
• peer-to-peer messaging–through Message (MSG) instructions
• messaging from programming devices
Unscheduled messaging on a ControlNet network is non-deterministic.
Your application and your configuration – number of nodes, application
program, network update time (NUT), amount of scheduled bandwidth
used, etc.– determine how much time there is for unscheduled messaging.
Module I/O Mapping
The I/O map for a module is divided into read words and write words. Read
words consist of input and status words, and write words consist of
output and configuration words. The number of read words or write
words can be 0 or more. The length of each I/O module’s read words and
write words vary in size depending on module complexity. Each I/O module
will support at least 1 input word or 1 output word. Status and configuration
are optional, depending on the module.
For example, a 16 point discrete input module will have up to 2 read words
and 1 write word.
Check the I/O map for each module for the exact mapping.
ControlNet Image
1 or 2 Words
Input Size
Module Image
Input
Not used
0 or 1 Words
Configuration Size
Not used
Delay
Time
41627
Delay
Time