Rockwell Automation 1756-SYNCH ControlLogix SynchLink Module User Manual - Manual (Page 39)

Publication 1756-UM521C-EN-P - July 2004
SynchLink Module Features 3-11
Electronic Keying
Instead of plastic mechanical backplane keys, electronic keying allows
the ControlLogix system to control what modules belong in the
various slots of a configured system.
During module configuration, you must choose one of the following
keying options for your 1756-SYNCH module:
• Exact Match
• Compatible Match
• Disable Keying
When the controller attempts to connect to and configure a
1756-SYNCH module (e.g. after program download), the module
compares the following parameters before allowing the connection
and configuration to be accepted:
• Vendor
• Product Type
• Catalog Number
• Major Revision - Change that affects the module’s function or
RSLogix 5000 interface
• Minor Revision - Change that does not affects the module’s
function or RSLogix 5000 interface (e.g. bug fixes)
The comparison is made between the keying information present in
the SynchLink module and the keying information in the controller’s
program. This feature can prevent the inadvertent operation of a
control system with the wrong module in the wrong slot. For
example, if you select Exact Match and a module with revision 2.10 is
placed in a location configured for a module with revision 2.18, the
controller does not make a connection to the new module because of
the mismatched revisions.