Allen-Bradley ControlNet Compact GuardLogix 1769, User Manual, Page: 90 / 100

Chapter 6 Messaging
Stagger the Messages
As you add messages to your project, you may have to coordinate the execution of
the messages. To avoid errors and assure that each message is processed, follow
these rules.
Rule 1 Enable no more than 16 messages at one time, including block transfers.
Rule 2
Enable no more than 10 of these types of messages at one time:
• CIP data table reads or writes that are not cached
• CIP generic
• PLC-2, PLC-3, PLC-5, or SLC (all types)
• Block transfer reads or writes that are not cached
If the number of messages in your application exceeds rules 1 and 2, then stagger
the execution of your messages. Here are some options:
•
•
Send each message in sequence.
•
Send the messages in groups that are within the limits of rules 1 and 2.
Program a message to communicate with multiple devices.
90 Rockwell Automation Publication CNET- UM001E-EN-P - June 2016