PT-G7828/G7728
Featured Functions
3-11
Setting
Description
Enable NTP authentication
The NTP authentication will be enabled if the checkbox
is selected
Authentication Key:
This part indicates the key that can be recognized by this device, and a maximum of 5 keys can be stored in the
device. Users can activate the key by selecting the ‘Trusted’ checkbox.
Setting
Description
Key ID
Indicate the ID of the key
Range: 1 to 65535,
Maximum of 5 key IDs can be stored
Key String
Defines the authentication key
Trusted
If selected, the key will be activated
NTP Client Settings
Setting
Description
Time Server/Peer Address
The time server or peer to sync to the ntp
Authentication
Enter the key ID that you want to be used for authentication. The
authentication key that user wants to be used to set the time
NTP/SNTP Server settings
Setting
Description
Enable NTP/SNTP Server
The device will be the NTP server if the checkbox selected.
IEEE 1588
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 depends 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 recognize significant fluctuations and use suitable averaging techniques in the algorithms
controlling the correction of the local 1588 clock will be good design means to achieve the highest time
accuracy.”
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