Siemens SWT 3000 Equipment Manual page 156

Installation and Commissioning
3.5 Device Configuration
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Figure 3-48
(1) Check box for activation of NU alarm
Line-Clock Synchronization
It is also possible to synchronize the clock via the connecting route (Line sync. mode off, Master, and Slave)
in one of the devices. The device that is to perform the synchronization is designated as the Master and the
device to be synchronized as the Slave.
That means it is only necessary to synchronize one device (the Master externally).
The line synchronization is performed once every 24 h at a configurable hour defined with Line sync. hour by
transmitting the synchronizing tone (fs). The difference in time between Master and Slave must not be
greater than ±30 s. Otherwise clock synchronization is not possible. The maximum difference in the time
between master and slave is thus the signal runtime.
If both devices are provided with external synchronizing pulses, select off in the Line sync. mode list box for
both devices. In this case, the synchronization between the devices is not activated.
156
Activation of NU Alarm in Case of USYNC Failure
Smart Communication, SWT 3000 Teleprotection, Equipment Manual
C53000-G6040-C605-1, Edition 03.2020