4. Appendix
4-7
TI 30A10A05-01E
n
Time synchronization with the Coordinated Universal Time (UTC)
To synchronize the Vnet/IP station time with the Coordinated Universal Time (UTC), connect
Vnet/IP bus 1 to the SNTP server that provides the UTC time. Alternatively, you can have a
redundant configuration by setting up an SNTP server for bus 1 and bus 2, respectively. If there is
an SNTP server in both bus 1 and bus 2, the station time is usually synchronized with the SNTP
server time in bus 1.
In Vnet/IP systems, the domain master station of the Vnet/IP domain connected to the SNTP
server synchronizes its time with the SNTP server time, and notifies the Vnet/IP stations within
the domain about the time. Between domains, the domain master station is considered as the
network time master. It synchronizes its time with the domain master stations that belong to the
same time group.
F040303E.ai
FCS
L2SW
Domain 1
L3SW
HIS
SCS
L2SW
Domain 2
HIS
/ENG
SENG
(Domain master)
(Network time master)
SNTP server
SNTP server
(slave)
Same Time Group
Figure Example of SNTP server connection
Set up an SNTP server for one domain in the time group. Set the following IP addresses for
SNTP servers by using the domain number to be connected:
• SNTP server for bus 1: 192.168.<domain number>.254
• SNTP server for bus 2: 192.168.<128 + domain number>.254
If there are multiple Vnet/IP domains in a time group, you can set the IP address for SNTP
servers only through the CENTUM engineering function of the domain that is connected to the
SNTP server. If the IP addresses of SNTP servers are blank, specify the IP addresses provided
earlier. You do not have to set the IP addresses for SNTP servers that do not belong to the
domain.
Aug.19,2011-00
Summary of Contents for Vnet/IP
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