Rockwell Automation Allen-Bradley SynchLink 1756-DM Series Design Manual page 16

1-4
Publication 1756-TD008A-EN-P - August 2002
Figure 1.2
Initial Start-Up
Master
Time adjustment
Slave
Synchronized Operation
Master
Slave
After a SynchLink time slave is synchronized with the time master,
each SynchLink frame that is transmitted serves as a 50 m S "tick" (or
mark) used for the periodic adjustment of its clock's 1 m S time base.
This process provides highly accurate results.
Figure 1.3
Beacon signal
synchronizes
SynchLink node
clocks
SynchLink 50 microsecond message frame
serves as a "tick" to keep clocks synchronized
Using the ControlLogix Coordinated System Time (CST)
The CST is the clocking mechanism used to achieve time
synchronization in a ControlLogix chassis; in the future, the CST will
be used in a DriveLogix system. The ControlLogix CST clock is a
64-bit clock on the backplane of the ControlLogix chassis. It has a 1 m S
resolution and is used as the main time reference for all modules
plugged into a chassis backplane.
For more information on how the ControlLogix CST affects the
operation of other ControlLogix products, see the ControlLogix System
User Manual, publication 1756-UM001.
Beacon Beacon Beacon
42982
42983
42984