Siemens SIMATIC CC712 Operating Instructions Manual page 88

Configuration
4.11 Maintenance
Synchronization method
You can synchronize the time of day manually or via NTP (Network Time Protocol).
Note
Time-of-day synchronization
For applications that require time-of-day synchronization, you should synchronize the time of
day of the device. If you do not synchronize the time of day regularly, there may be
deviations of several seconds each day between the device and its communication partners.
System time
● Using NTP server
Enable the option if the time of day is to be synchronized via NTP.
When this option is disabled, you can set the time of day of the device manually.
● NTP server address
Enter the address of the NTP server as IPv4 address or as DNS name.
● Synchronization cycle (s)
Specifies the cycle of the time-of-day queries to the NTP server.
Range of values in seconds: 16..1024
● Time Zone
In NTP mode, it is generally UTC (Universal Time Coordinated) that is transferred. This
corresponds to GMT (Greenwich Mean Time).
The time offset from UTC can be set by configuring the local time zone.
● NTP (secure)
The secure method NTP (secure) uses authentication with symmetrical keys.
Parameters for the NTP (secure) method
● Key ID
Key ID of the NTP server. Numeric value.
Range of values: 1..65534
● Hash algorithm
Select alternatively:
– SHA-1
– MD5
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Operating Instructions, 05/2019, C79000-G8976-C503-01
SIMATIC CC712