Rockwell Automation 1756-SYNCH ControlLogix SynchLink Module User Manual - Manual (Page 36)

Publication 1756-UM521C-EN-P - July 2004
3-8 SynchLink Module Features
Module-Defined Data Tags
When you create a module, RSLogix 5000 creates module-defined data
types and tags. These tags allow you to access the Configuration,
Input and Output Data of the module via the controller’s ladder logic.
The types of tags created vary, depending on which communications
format you choose when creating a module. There are three types
of tags:
• Configuration Data Tags
• Input Data Tags
• Output Data Tags
For a complete listing of all the module-defined data tags available on
your SynchLink module, see Appendix E.
Internal Scan on SynchLink Module
Every 500μS, the SynchLink module scans its internal hardware and
captures a “snapshot” of the data there. This data is then sent to the
local owner-controller at the Change of State (COS) instance,
independent of the requested packet interval (RPI) rate. But,
depending on the communications formats chosen during module
configuration, data types are transmitted between SynchLink nodes
(via the fiber optic cable) at various rates and may be transmitted
multiple times between the 500μS snapshots.
IMPORTANT
The transfer rate times listed in Table 3.4 and Table 3.5
only represent the rate at which data is passed between
SynchLink modules over the fiber optic cable.
Although the data is passed over the fiber optic cable
at various rates, according to the communications
format choices, the owner-controllers in each local
chassis only receive the data after the local
SynchLink module’s internal scan every 500μS.