Time Synchronization - Siemens SIMATIC S7-1500 System Manual
Redundant system
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Also See for SIMATIC S7-1500:
- Function manual (402 pages) ,
- System manual (393 pages) ,
- Manual (188 pages)
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12.7
Time synchronization
Introduction
All S7-1500R/H CPUs have 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 CPUs take into account the time change caused by daylight saving time.
In redundant mode, the two CPUs of the S7-1500R/H redundant system constantly
synchronize their internal clocks.
You can synchronize the time of the CPUs using the NTP procedure.
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 servers, the most reliable and most
accurate time is calculated and the time of day on the S7-1500R/H 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. As sources for time
synchronization, you perform addressing via the IP addresses (e.g. a communications
processor or HMI device) or via the FQDN (Fully Qualified Domain Name).
The update interval defines the interval between the time queries (in seconds). The value
range for the interval is 10 seconds to one day. In NTP mode, it is generally UTC (Universal
Time Coordinated) that is transferred. UTC corresponds to GMT (Greenwich Mean Time).
Conditions
• In the S7-1500R/H redundant system, you need to configure time synchronization in NTP
mode for each CPU individually. If possible, use the same settings for both CPUs.
• You define the settings for the time synchronization via NTP method in the "Properties >
General > Time" parameter group.
• Make sure that the primary CPU maintains a constant connection to the NTP server. The
backup CPU then receives its synchronized time of day from the primary CPU.
Procedure
Proceed as follows to enable time synchronization for a CPU:
1. Configure the interface properties in the "Properties > General > Time" parameter group.
2. Set the "Set NTP server in project" value at the "Time synchronization" parameter.
3. Enter the IP addresses of up to four NTP servers at parameter "Server 1-4".
4. Set the time interval for time queries at the parameter "Update interval".
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
Commissioning
12.7 Time synchronization
425
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