Rockwell Automation 1715-OF8I Redundant I/O System User Manual - Manual (Page 268)

268 Rockwell Automation Publication 1715-UM001C-EN-P - March 2014
Appendix B Electronic Keying
EXAMPLE In the following scenario, Compatible Keying prevents I/O communication:
• The module configuration is for a 1756-IB16D module with module revision 3.3. 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 is lower than expected and is not
compatible with 3.3.
EXAMPLE In the following scenario, Compatible Keying allows I/O communication:
• The module configuration is for a 1756-IB16D module with module firmware revision 2.001.
The physical module is a 1756-IB16D module with module firmware revision 3.002. 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
Cat. No. = 1756-IB16D
Major Revision = 3
Minor Revision = 3
Physical Module
Vendor = Allen-Bradley
Product Type = Digital Input Module
Cat. No. = 1756-IB16D
Major Revision = 3
Minor Revision = 2
Communication is prevented
Module Configuration
Vendor = Allen-Bradley
Product Type = Digital Input Module
Cat. No. = 1756-IB16D
Major Revision = 2
Minor Revision = 1
Physical Module
Vendor = Allen-Bradley
Product Type = Digital Input Module
Cat. No. = 1756-IB16D
Major Revision = 3
Minor Revision = 2
Communication is allowed