Allen-Bradley 1756-L65 ControlLogix 5565, Programming Manual

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14 Rockwell Automation Publication 1756-PM004D-EN-P - September 2012
Chapter 1 Communicate with I/O Modules
Compatible Module
Compatible Module indicates that the module determines whether to accept or
reject communication. Different module families, communication adapters, and
module types implement the compatibility check differently based on the family
capabilities and on prior knowledge of compatible products.
Compatible Module is the default setting. Compatible Module allows the
physical module to accept the key of the module configured in the software,
provided that the configured module is one the physical module is capable of
emulating. The exact level of emulation required is product and revision specific.
With Compatible Module, you can replace a module of a certain Major Revision
with one of the same catalog number and the same or later, that is higher, Major
Revision. In some cases, the selection makes it possible to use a replacement that is
a different catalog number than the original. For example, you can replace a 1756-
CNBR module with a 1756-CN2R module.
Release notes for individual modules indicate the specific compatibility details.
When a module is created, the module developers consider the module’s
development history to implement capabilities that emulate those of the previous
module. However, the developers cannot know future developments. Because of
this, when a system is configured, we recommend that you configure your module
using the earliest, that is, lowest, revision of the physical module that you believe
will be used in the system.