• NTP Server Time Clock: If time servers are configured and present on the
network (see chapter 6 for configuration details), the Ethernet interface’s built-in
clock is periodically synchronized to the clock from one to three NTP servers on the
network. The Ethernet interface periodically requests time from the servers and uses
the time from the most accurate server (based on NTP stratum number).
CPU Ethernet
interface
CPUE05
time
clock
NTP Time
CPU
time
clock
NTP Time
Server on
Network
timestamp
All Ethernet interfaces that have been configured to use Network Time Protocol will have
updated, synchronized timestamps because they are all controlled by the NTP server
clock. Therefore, accurate timing comparisons between exchanged data can be made. For
example, if several PLCs sent alarm data, it might be helpful to know the order in which
the alarms occurred.
Multiple NTP servers can be used to improve the availability of time servers.
When the time is obtained from an NTP server, dates from January 1, 1970 are supported
by the Ethernet Interface.
13.4.5 Configuring NTP for the CPUE05 Ethernet
Interface
This feature is supported in IC200CPUE05-HK and previous versions only.
To implement Network Time Protocol in the Ethernet interface in CPUE05, the IP address
of one to three NTP Time Servers are specified in the PLC Ethernet configuration. Refer
to chapter 6, the section, Configuring the Ethernet Interface for details. CPUE05 does not
support multicast NTP operation; multiple NTP servers may be specified individually.
The Ethernet interface in CPUE05 always operates in client mode. It will synchronize to
an NTP time server, but it will not synchronize other devices on the network.
Time synchronization takes multiple message exchanges to reach maximum precision.
Based on the default configuration of poll times, NTP synchronization should occur
approximately 2 minutes after a time server has been established.
Ethernet Communications GFK-1503E User Manual 257
For public disclosure
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