20 Gear Drive, Plymouth Ind. Park, Terryville, CT 06786
Tel: (860) 585-1254 Fax: (860) 584-1973 http://www.amci.com
105
TASK 3 (
OPTIONAL
)
D
ISTRIBUTED
C
LOCK
- SYNC0 S
ETUP
By default, the networked Driver acts on the data from the EtherCAT master as soon as it is transmitted to the
device. This mode of operation is called “SM-Synchron”. The data transfer is synchronized with the Sync-
Manager 2 event. This synchronization is more than adequate for most machine types.
On very high speed machines, or large machines that require more than one EtherCAT transfer to update all of
the I/O, it may be necessary to use the EtherCAT Distributed Clock mechanism to synchronize the start of
moves with other motion axes or other devices on the EtherCAT network.
Using the Distributed Clock feature adds complexity to the system that may not be needed. On large
machines that require more than one EtherCAT transfer to update all of the I/O, configure the network to
update all of the axes with one transfer. This may eliminate the need to use the DC functionality on large
machines.
3.1 Verify Main PLC Task Timing
1) In the
Solutions Explorer
, expand out
System
Tasks
so that the tasks are visible. Double click on the task
assigned to the main PLC. This task is typically named
PlcTask
. In the windows that open, note the value
for Cycle Ticks and its time in milliseconds. These values are typically 10 ticks and 10.000 milliseconds.
You can change the timing of the main task here, but this will affect the timing of every program that
runs under this task.
Figure T3.1 Main PLC Task Timing
2) If this value is between 2 and 50 milliseconds and the correct update time for the Networked Driver, skip to
step 3.3. When setting the
SYNC 0 -> Sync Unit Cycle
multiplier in step 6 of 3.3, use a value of 1.
3) If the timing in step 1 above is not correct for the Networked Driver, but the correct time is an integer
multiple of this timing, then skip to step 3.3. When setting the
SYNC 0 -> Sync Unit Cycle
multiplier in
step 6 of 3.3, use the correct integer multiplier.
4) If the timing is step 1 above is not correct for the Networked Driver, and the correct time is
not
an integer
multiple of this timing, then proceed with step 3.2.
This chapter outlines the steps need to configure the Networked Driver to syn-
chronize to the Sync0 signal from the Distributed Clock (DC) feature instead of the
SyncManager 2 event. This configuration is optional.
