Rockwell Automation AADvance Controller Demo Unit - Manual (Page 41)

Document: 553850 Issue 1.2: March 2011 4-7

For non-fault tolerant operation, define one SNTP server for only one
processor. The other processors will automatically synchronize to it and will
inherit the time.

For fault-tolerant SNTP client operation, define more than one server address.
3) Select the server version.

Choose SNTPv1, SNTPv2, SNTPv3, SNTPv4 or Unknown.

If you do not know the version of NTP/SNTP that the server offers, choose
Unknown. This will disable some validation of the incoming signal.
4) Set the Mode to Unicast or Broadcast as required.

In Broadcast mode the SNTP client will passively wait for regular broadcasts
from the server. This reduces network traffic and hence the load on the
servers.

In Unicast mode the SNTP client will actively poll as many servers as are
configured every few seconds and use their responses. The polling rate (19s) is
based on the drift rate of the real-time clock and cannot be configured.
5) Click Apply.
Configure the Controller as an SNTP Server
The AADvance controller can fulfill the role of one or more SNTP servers (one for
each processor) to provide a network time signal throughout the network.
To enable serving time on an interface it is necessary to specify the direct broadcast
address for that interface. This works for broadcast or unicast modes. This method of
configuring is derived from the NTP configuration command language.
For an interface, the directed broadcast address
= ( (IP address for interface) bitwise-and (subnet-mask) ) bitwise-or (bitwise-not
subnet-mask)
For example, if the IP address for an interface is 10.10.1.240 and its subnet-mask is
255.255.255.0 then the directed broadcast address is:
= ((10.10.1.240) bitwise-and (255.255.255.0)) bitwise-or (bitwise-not
255.255.255.0)
= (10.10.1.0) bitwise-or (0.0.0.255)
To configure the SNTP servers service do the following: