Siemens Simatic S7-1500 / ET 200MP - Time Synchronization

Commissioning
12.8 Time synchronization
Automation system
278 System Manual, 01/2023, A5E03461182-AK
Size of files and size of the SIMATIC memory card
Note
SIMATIC memory card
Make sure that there is en
ough available storage space on your SIMATIC memory card for
downloading projects.
To download and back up projects, the project size and the size of the files on the SIMATIC
memory card must be less than 2
GB.
Do not manipulate any contents in the OMSSTORE directory on the SIMATIC memory card.
You can find information on reading out the memory usage of the CPU and the SIMATIC
memory card in the Structure and Use of the CPU Memory
(https://support.industry.siemens.com/cs/de/de/view/59193101/en) Function Manual.
12.8 Time synchronization
Introduction
All CPUs are equipped with an internal clock. The clock shows:
• The time of day with a resolution of 1 millisecond
• The date and the day of the week
The CPU take into account the time change caused by daylight saving time.
You can synchronize the time of the CPUs with an NTP server in NTP mode.
Principle of operation
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 synchronize
the time of day of up to a maximum of four NTP servers. You address a communications
processor or an HMI device, for example, as sources for time synchronization via the IP
addresses.
The update interval defines the interval between the time queries (in seconds). The value of
the interval ranges between 10 seconds and one day. In NTP mode, it is generally UTC
(Universal Time Coordinated) that is transferred. UTC corresponds to GMT (Greenwich Mean
Time).