Rockwell Automation 1756-SYNCH ControlLogix SynchLink Module User Manual - Manual (Page 40)

Publication 1756-UM521C-EN-P - July 2004
3-12 SynchLink Module Features
Table 3.6 describes the keying options available with your 1756-SYNCH
module.
Table 3.6
Keying option: Definiton:
Exact Match All of the parameters listed above must match or the inserted module will reject a connection to the controller.
Compatible Match The Compatible Match mode allows a 1756-SYNCH module to determine whether it can emulate the module
defined in the configuration sent from the controller.
With 1756-SYNCH modules, the module can emulate older revisions. The module will accept the configuration
if the configuration’s major.minor revision is less than or equal to the physical module’s revision.
For example, if the configuration contains a major.minor revision of 2.10, the module inserted into the slot
must have a firmware revision of 2.10 or higher for a connection to be made. When a module is inserted with
a major.minor revision that is less than the revision for which the slot is configured (i.e. the module has a
revison of 1.17 and the slot is configured for a module with revision 2.18), no connection is made between the
controller and the I/O module.
TIP
We recommend using Compatible Match whenever possible. Remember, though, with
major revision changes, the module only works to the level of the configuration.
If a slot is configured for a module with major.minor revision of 1.17 and you insert a
module with a major.minor revision of 2.10, the module works at the 1.17 level, with
respect to module functions that are related to RSLogix 5000 such as interface changes.
However, bug fixes that are affected by the module’s firmware, would work at the 2.10
revision level.
If possible, we suggest you make sure configuration is updated to match the revision
levels of all I/O modules. Failure to do so may not prevent the application from working
but may defeat the purpose of upgrading your modules’ revision levels.
Disable Keying The inserted module attempts to accept a connection to the controller regardless of its type.
ATTENTION
Be extremely cautious when using the disable keying option; if used incorrectly, this
option can lead to personal injury or death, property damage or economic loss.
If keying is disabled, a controller makes a connection with most modules of the same type as that used in the
slot configuration. Even if keying is disabled, a controller will not establish a connection if the slot is
configured for one module type (e.g. input module) and a module of another type (e.g. output module) is
inserted in the slot.