Time Synchronization; Time-Of-Day Synchronization Of The Cpu - Siemens SIMATIC S7-1500 System Manual

11.9

Time synchronization

11.9.1

Time-of-day synchronization of the CPU

NTP procedure
All CPUs are equipped with an internal clock. The clock always shows the time-of-day with a
resolution of 1 millisecond and the date including the day of the week. The time adjustment
for daylight saving time is also taken into account.
You can update the time of the CPUs using the NTP procedure with an NTP server. NTP
(Network Time Protocol) is a standard for synchronizing clocks.
In NTP mode, the device sends time queries at regular intervals (in client mode) to the NTP
server in the subnet (LAN). Based on the replies from the server, the most reliable and most
accurate time is calculated and the time of day on the CPU is synchronized. The advantage
of this mode is that it allows the time to be synchronized across subnets. You can configure
the IP addresses of up to a maximum of four NTP servers. You address the sources for the
time-of-day synchronization via IP addresses, for example, an HMI device.
The update interval defines the interval between the time queries (in seconds). The value of
the interval ranges between 10 seconds and one day. The NTP procedure generally uses
UTC (Universal Time Coordinated). UTC corresponds to GMT (Greenwich Mean Time).
NTP server for the SIMATIC Drive Controller
In STEP 7, you enable time synchronization using the NTP procedure. In STEP 7, you can
configure up to four NTP servers for the SIMATIC Drive Controller.
If you have enabled time synchronization via NTP for the CPU, then you can enter the IP
addresses of up to four NTP servers in the user program. Use the "T_CONFIG" instruction.
Enabling time synchronization via NTP server
Proceed as follows to enable time-of-day synchronization via NTP servers for the CPU:
1. In the Inspector window, navigate to the properties of the CPU to "General" >
"PROFINET interface" > "Time-of-day synchronization".
2. Select the "Enable time synchronization via NTP server" option.
Configuring NTP server in STEP 7
Proceed as follows to configure one or more NTP servers for the CPU:
1. In the Inspector window, navigate to the properties of the CPU to "General" >
"PROFINET interface" > "Time-of-day synchronization".
2. Enter the IP addresses of up to 4 NTP servers at the parameters "Server 1" to "Server 4".
3. Set the time interval of the time queries at the parameter "Update interval". Set the
update interval to between 10 s and 86400 s.
SIMATIC Drive Controller
System Manual, 11/2019, A5E46600094-AA
Commissioning
11.9 Time synchronization
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