Rockwell Automation 1756-IF4FXOF2F ControlLogix High-speed Analog I/O Module - Manual (Page 121)

Rockwell Automation Publication 1756-UM005B-EN-P - January 2013 121
Appendix
C
Use Message Instructions to Perform
Run-time Services and Module Reconfiguration
You can use ladder logic to perform run-time services on your module. For
example,
page 77 shows how to unlatch alarms on the high-speed analog I/O
module using the module properties wizard. This appendix provides an example
of how to unlatch those same alarms with ladder logic and message instructions.
In addition to performing run-time services, you can use ladder logic to change
the configuration, as described in
Chapter 5 . Some parameters may also be
changed through ladder logic.
Message Instructions When programming your ControlLogix high-speed analog I/O module, you can
use message instructions to send services to the module. Message instructions
send an explicit service to the module, causing specific behavior to occur, for
example, unlatching an alarm.
Message instructions have the following characteristics:
• Messages use unscheduled portions of system communication bandwidth.
• One service is performed per instruction.
• Performing module services does not impede module functionality, such
as sampling inputs or applying new outputs.
Topic Page
Message Instructions 121
Add the Message Instruction 123
Reconfigure the Module with a Message Instruction 128
IMPORTANT The enhanced message instruction is available only if you are using
RSLogix 5000 software, version 10 or later.