Allen-Bradley ControlLogix L7 User Manual

Rockwell Automation Publication 1756-UM001M-EN-P - February 2012 217
Using Electronic Keying Appendix B
Disabled Keying
Disabled Keying indicates the keying attributes are not considered when
attempting to communicate with a module. Other attributes, such as data size and
format, are considered and must be acceptable before I/O communication is
established. With Disabled Keying, I/O communication may occur with a
module other than the type specified in the I/O Configuration tree with
unpredictable results. We generally do not recommend using Disabled Keying.
EXAMPLE
In the following scenario, Compatible Keying allows I/O communication:
The module configuration is for a 1756-IB16D module with module revision 2.1. The physical
module is a 1756-IB16D module with module revision 3.2. In this case, communication is
allowed because the major revision of the physical module is higher than expected and the
module determines that it is compatible with the prior major revision.
Module Configuration
Vendor = Allen-Bradley
Product Type = Digital Input Module
Catalog Number = 1756-IB16D
Major Revision = 2
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 allowed.
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.
ATTENTION: Be extremely cautious when using Disabled Keying; if used
incorrectly, this option can lead to personal injury or death, property
damage, or economic loss.

Allen-Bradley ControlLogix L7 Specifications

General

Brand	Allen-Bradley
Model	ControlLogix L7
Category	Controller
Language	English