Rockwell Automation 1769-SM1 Compact I/O to DPI/SCANport Module - Manual (Page 64)

5-10 MicroLogix 1500 Ladder Example Program
This section provides information and examples that explain how to use
Explicit Messaging to monitor and configure the 1769-SM1 and
connected drive(s).
Explicit messaging with the 1769-SM1 is supported only by the
MicroLogix 1500 LRP processor and RSLogix 500 (version 6.1 or
higher).
Important: The MicroLogix 1500 LRP processor supports messaging
only for the first 2 I/O modules capable of messaging.
About Explicit Messaging
Explicit Messaging is used to transfer data that does not require
continuous updates. With Explicit Messaging, you can configure and
monitor a drive’s parameters in the controller’s ladder program.
Formatting Explicit Messages
Each message must be formatted as shown in Figure 5.5 . Refer to
Table 5.A for a description of the data that is required in each box.
Using Explicit Messaging
!
ATTENTION: Hazard of injury or equipment damage exists. The
examples in this publication are intended solely for purposes of
example. There are many variables and requirements with any
application. Rockwell Automation does not assume responsibility or
liability (to include intellectual property liability) for actual use of the
examples shown in this publication.
!
ATTENTION: Hazard of equipment damage exists. If Explicit
Messages are programmed to write parameter data to Non-Volatile
Storage (NVS) frequently, the NVS will quickly exceed its life cycle
and cause the drive to malfunction. Do not create a program that
frequently uses Explicit Messages to write parameter data to NVS.
Datalinks do not write to NVS and should be used for frequently
changed parameters.
TIP: A message file must be created for use by the message
instructions. Create a new data file having type = Message, and
containing at least one element for each message instruction in the ladder
program.