User Manual Instruction Manual

Rockwell Automation Publication 193-UM014B-EN-P December 2011 63
Chapter 7
Logic Explicit Messaging
CompactLogix, ControlLogix, and SoftLogix controllers can read and write
specific information to and from DeviceNet modules on the same DeviceNet
network through the EtherNet/IP Communications Auxiliary using Explicit
Messaging.
The following steps configure a ControlLogix explicit message using the MSG
instruction to read diagnostic parameters from an E3 Plus Model and EC5
Overload Relay.
1. In an interger array named MSG_Read_Request, define the number of
attributes to read and list the specific attribute numbers.
The MSG instruction will return in an integer array with the first integer
representing the following information:
• number of attributes
• first attribute number being returned
• first attribute number data status
• first attribute data…
• last attribute number being returned
• last attribute number data status
• last attribute data
Scan List I/O Size Produced I/O data from the fourth scan list entry.
Scan List I/O Size Produced I/O data from the fifth scan list entry.
Scan List I/O Size Produced I/O data from the sixth scan list entry.
2 bytes Data Link 1 Data
2 bytes Data Link 2 Data
2 bytes
: :
Data Link 3 Data
: :
2 bytes Data Link 48 Data
Byte Size Contents