Rockwell Automation Allen-Bradley SynchLink 1756-DM Series Design Manual page 55

Drive Module Focus
In this configuration:
· SynchLink modules are required if you want to synchronize the
Drive modules between chassis.
· Drive module SynchLink connections pass data and SynchLink
node clock timing information. Drive modules synchronize their
clocks to the CST reference on the ControlLogix backplane.
Figure 4.12
SynchLink
1756-SYNCH
Table 4.13 lists more information about this configuration.
Table 4.13
Category:
Time synchronization
Data transfer
Restrictions
(1)
The local ControlLogix controller must move the axis or buffered data for a 1756-SYNCH module. For the
1756-DMxxx module, the module's VPL microprocessor must move the data. For more information, see
page 1-7.
Hub
1756-DMxxx 1756-DMxxx
1756-SYNCH
Explanation:
Master -
Slaves -
The CST clocks are synchronized across all chassis.
The SynchLink node clocks are synchronized across all SynchLink
nodes. The VPL values are synchronized across all 1756-DMxxx
modules because the modules are synchronized by the respective
CST values in each chassis.
· Typically, this configuration is used to transfer direct data.
· If you want to pass buffered data, the local controller at
each node must pass the data.
· You can only transfer axis data between SynchLink
modules.
· You can use a maximum of 10 devices in any daisy chain
portion of the system.
1756-SYNCH module
1756-SYNCH modules and 1756-DMxxx
series modules
(1)
Publication 1756-TD008A-EN-P - August 2002
4-17
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