Allen-Bradley Logix5000 Programming Manual

Publication 1756-PM004C-EN-P - October 2009 15
Communicate with I/O Modules Chapter 1
Exact Match
Exact Match keying requires all keying attributes, that is, Vendor, Product
Type, Product Code (catalog number), Major Revision, and Minor Revision, of
the physical module and the module created in the software to match precisely
in order to establish communication. If any attribute does not match precisely,
I/O communication is not permitted with the module or with modules
connected through it, as in the case of a communication module.
Use Exact Match keying when you need the system to verify that the module
revisions in use are exactly as specified in the project, such as for use in
highly-regulated industries. Exact Match keying is also necessary to enable
Automatic Firmware Update for the module via the Firmware Supervisor
feature from a Logix5000 controller.
IMPORTANT
Changing electronic keying selections online may cause the I/O
communication connection to the module to be disrupted and
may result in a loss of data.
EXAMPLE
In the following scenario, Exact Match keying prevents I/O
communication:
The module configuration is for a 1756-IB16D module with module
revision 3.1. The physical module is a 1756-IB16D module with
module revision 3.2. In this case, communication is prevented because
the Minor Revision of the module does not match precisely
.
Module Configuration
Vendor = Allen-Bradley
Product Type = Digital Input
Module
Catalog Number = 1756-IB16D
Major Revision = 3
Minor Revision = 1
Physical Module
Vendor = Allen-Bradley
Product Type = Digital Input
Module
Catalog Number = 1756-IB16D
Major Revision = 3
Minor Revision = 2
Communication is prevented

Allen-Bradley Logix5000 Specifications

General

Brand	Allen-Bradley
Model	Logix5000
Category	Controller
Language	English