User manual

Using the NTPTime Service
33002479 06 07/2008 245
NTP Time
Synchronization
and Time Stamps
The Schneider Electric Ethernet interface module NOE 771 11 provides the source
time-synchronization signal sent to a controller. The module’s firmware includes an
NTP client, which provides time synchronization.
To read the clock from the PLC application:
z Use the R_NTPC function block (see Using the R_NTPC Block for Time
Synchronization, p. 247) in either MAST, FAST, or Interrupt sections.
On an Ethernet network, all controllers should be synchronized with the same NTP
server.
Action Result
NTP Client requests a time synchronization
signal from an NTP server. (Request is sent
over an Ethernet network.)
NTP Server responds with a signal.
NTP Client stores the time.
NTP Client sends a message to the
controller’s clock system counter.
The controller updates its internal clock with
the following granularity:
z 1 ms
CPS CPU NOE77111
Clock
System
Counter
NTP
Client
NTP Request
NTP Response
Ethernet
Network
NTP
Server
Modicon Quantum System
EN
R_NTPC
EN0
OUT1
OUT2
STATUS