CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
151
Time synchronization and time stamping
10
Definition of time synchronization
Time synchronization refers to the process in which various S7 stations receive or retrieve
their local time from a central time source (central time transmitter/time server).
Time-of-day synchronization is required when the time sequence of events from different
stations is to be evaluated.
Interfaces
Time-of-day synchronization is possible across all interfaces of the CPU 410:
●
PROFINET IO interface via Industrial Ethernet
Time-of-day synchronization using the NTP method; the CPU is the client.
Time-of-day synchronization using the SIMATIC method as master or slave. The PTCP
master is also possible for synchronization of IO devices of type ET 200SP HA.
●
Within the station (in the AS) using the S7-400 backplane bus
You can configure the CPU as a time master or a time slave.
●
PROFIBUS DP interface
You can configure the CPU as a time master or a time slave.
Time-of-day synchronization via the PROFINET IO interface
With the PROFINET IO interface, time-of-day synchronization is possible using the NTP
method and the SIMATIC method. The CPU 410 is the client in this case.
You can configure up to four NTP servers. You can set an update interval of between
10 seconds and 1 day. An NTP request of the CPU 410 always occurs every 90 minutes for
times greater than 90 minutes.
If you synchronize the CPU 410 in the NTP method, you should use SICLOCK or an NTP
server on the OS.
Time-of-day synchronization is also possible via Ethernet MMS (Simatic method on
Ethernet) as master or slave. NTP can in this case be combined with the SIMATIC method.
CPU 410 as time slave
If the CPU 410 is a time slave on the S7-400 backplane bus, synchronization is via the CP
with a clock connected to the LAN.
You can use a CP to forward the time to the S7-400 station. If the CP supports a direction
filter, the CP must be configured for time forwarding with the "from LAN to station" option.