EDS-510A Series User’s Manual
Featured Functions
3-11
NOTE
Changing the time zone will automatically correct the current time. You should
configure the
time zone before setting the time
.
Time Server IP/Name
Setting
Description
Factory Default
1st Time Server IP/Name
IP or Domain address (e.g., 192.168.1.1 or
time.stdtime.gov.tw or time.nist.gov).
2nd Time Server IP/Name
The EDS-510A will try to locate the 2nd NTP
Server if the 1st NTP Server fails to connect.
None
Time Server Query Period
Setting
Description
Factory Default
Query Period
This parameter determines how frequently the
time is updated from the NTP server.
600 seconds
IEEE 1588 PTP
The following information is taken from the NIST website at http://ieee1588.nist.gov/intro.htm:
Time measurement can be accomplished using the IEEE Standard for a Precision Clock
Synchronization Protocol for Networked Measurement and Control Systems (IEEE 1588-2008) to
synchronize real-time clocks incorporated within each component of the electrical power system
for power automation applications.
IEEE 1588, which was published in November 2002, expands the performance capabilities of
Ethernet networks to control systems that operate over a communication network. In recent years
an increasing number of electrical power systems have been using a more distributed architecture
with network technologies that have less stringent timing specifications. IEEE 1588 generates a
master-slave relationship between the clocks, and enforces the specific timing requirements in
such power systems. All devices ultimately get their time from a clock known as the grandmaster
clock. In its basic form, the protocol is intended to be administration free.
How does an Ethernet Switch Affect 1588 Synchronization?
The following content is taken from the NIST website at http://ieee1588.nist.gov/switch.htm:
An Ethernet switch potentially introduces multi-microsecond fluctuations in the latency between
the 1588 grandmaster clock and a 1588 slave clock. Uncorrected these fluctuations will cause
synchronization errors. The magnitude of these fluctuations depend on the design of the Ethernet
switch and the details of the communication traffic. Experiments with prototype implementations
of IEEE 1588 indicate that with suitable care the effect of these fluctuations can be successfully
managed. For example, use of appropriate statistics in the 1588 devices to recognized significant
fluctuations and use suitable averaging techniques in the algorithms controlling the correction of
the local 1588 clock will be the good design means to achieve the highest time accuracy.